Forum: Mystical Realm BBS

DAY1SVR: Day 1 Convective Outlook

From COD Weather Processor @1:2320/107 to All on Thu Aug 27 01:00:32 2026

ACUS01 KWNS 270100
SWODY1
SPC AC 270058

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 PM CDT Wed Aug 26 2026

Valid 270100Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
CENTRAL HIGH PLAINS...AND ALSO FROM THE ARKLATEX TO THE ARKLAMISS
REGIONS...

...SUMMARY...
Isolated to widely scattered strong to severe thunderstorms remain
possible tonight across parts of the central and southern High
Plains, parts of Arkansas into the lower Mississippi Valley, and
parts of the Midwest and Ohio Valley.

...Central/southern High Plains...
Widely scattered strong to severe storms are ongoing this evening
across parts of the central/southern High Plains. The most favorable environment resides from eastern CO into western KS, with moderate
buoyancy and effective shear of 30-40 kt within a northwesterly flow
regime. The strongest discrete cells in this area will continue to
pose a threat of hail and localized severe gusts. Some modest
clustering remains possible with time, which could result in at
least an isolated severe-wind threat as convection spreads into
western KS later tonight.

Deep-layer flow/shear is generally weaker across the southern High
Plains, but localized strong to severe gusts will remain possible
within the well-mixed environment through at least dusk.

...AR into the Lower MS Valley...
Widespread deep convection from southeastern OK into
central/southern AR may eventually evolve into a loosely organized, outflow-driven cluster with time this evening. This could result in
a threat for scattered wind damage spreading into northern LA
through the evening, with an isolated threat possible later tonight
as storms approach the LA/MS Gulf Coasts.

...Midwest/Ohio Valley...
Scattered storms are ongoing from parts of Lower MI into parts of
the Midwest/Ohio Valley. The combination of moderate buoyancy and
marginal deep-layer shear (generally 25-35 kt of effective shear)
has only been supportive of an isolated severe threat thus far. No
substantial improvement in the environment is expected through the
evening, but ongoing storms may continue to pose an isolated severe
threat before convection generally subsides later tonight.

..Dean.. 08/27/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 27 05:58:06 2026

ACUS01 KWNS 270557
SWODY1
SPC AC 270555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Thu Aug 27 2026

Valid 271200Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC AND NORTHEAST...AND ALSO ACROSS PARTS OF
WESTERN/CENTRAL NE INTO NORTHWEST KS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Northeast today. Damaging wind, hail and a tornado or two may
accompany these storms. Large to very large hail and severe gusts
are also possible across parts of western Nebraska and northwest
Kansas.

...Mid-Atlantic/Northeast into parts of the central/southern
Appalachians...
An upper trough will remain in place over much of the eastern CONUS
today. Moderate destabilization will be possible along/ahead of a
weak surface trough/front extending from central NY/PA into the central/southern Appalachians. Scattered thunderstorm development is
expected by mid/late afternoon, with sufficient deep-layer
flow/shear for some storm organization (especially from the northern Mid-Atlantic into the Northeast). The strongest cells/clusters will
be capable of producing scattered damaging winds and at least
isolated hail. Modestly enlarged low-level hodographs may also
support some brief-tornado potential. Some severe threat may persist
into the evening before storms weaken and/or move offshore.

Father south, deep-layer flow/shear will be weaker into parts of the central/southern Appalachians, but scattered storm development
within a relatively warm and well-mixed environment will support
potential for localized strong/damaging gusts.

...Central Plains...
Moderate to locally strong destabilization is expected across parts
of the central High Plains this afternoon, beneath modest
northwesterly mid/upper-level flow. While large-scale ascent will
generally remain rather modest, a subtle midlevel vorticity maximum
may aid in isolated to widely scattered storm development from far
southwest SD into western/central NE. Deep-layer shear will be
sufficient for supercells, with steep lapse rates and relatively
elongated hodographs supporting potential for large to very large
hail, in addition to a threat for localized severe gusts. 00Z CAM
guidance shows some uptick in storm coverage within this favorable
environment, and a 15% hail area has been added for parts of
west-central NE into northwest KS. Some guidance (notably the 00Z
HRRR) also shows upscale growth and an attendant swath of
severe-wind potential, though this scenario remains more uncertain.
Greater wind probabilities may eventually be needed if confidence
increases in the MCS scenario.

Surrounding the Level-2/Slight Risk, a more isolated threat of
severe hail and wind may accompany the strongest cells from parts of
the Raton Mesa and CO Front Range vicinity into eastern WY.

...Western/central Montana...
Despite rather limited low-level moisture, widely scattered storm
development is expected this afternoon across parts of
western/central MT, aided by strong heating and the influence of a
midlevel shortwave trough and jet maximum that are forecast to crest
the amplified upper ridge that is covering much of the interior
West. Steep lapse rates will support potential for localized
downbursts and strong to severe outflow gusts as storms spread east-northeastward across MT.

...Northeast NV/northwest UT/southeast ID...
High-based storm development is also expected from parts of
northeast NV into northwest UT and southeast ID. While deep-layer
flow and storm organization will likely be somewhat weaker compared
to areas farther north, steep lapse rates and large DCAPE will
support potential for strong to severe outflow gusts from this
afternoon into the early evening.

...South-central TX into the LA Gulf Coast region...
Uncertainty remains regarding how far south an ongoing storm cluster
and its attendant outflow will move across parts of LA/MS early this
morning. If this cluster persists to the beginning of the forecast
period (as forecast by the 00Z HRRR), then a localized wind-damage
threat will be possible near the immediate LA/MS Gulf Coast before
storms move offshore. If the cluster weakens and more substantial
recovery and diurnal destabilization occurs later today (as forecast
by more recent HRRR runs and some other HREF members), then storm
redevelopment will be possible by afternoon, potentially aided by a
remnant MCV. This scenario could also result in a localized
wind-damage threat.

Farther west, scattered storm development is forecast across
south-central TX this afternoon, near a weak southward-moving cold
front. Deep-layer shear will likely remain quite weak, but moderate
buoyancy, large PW, and steep low-level lapse rates will support
potential for localized downbursts. Despite the weak shear, the
northerly flow regime may result in one or more outflow-driven
clusters that will move southward into the early evening before
weakening.

..Dean/Weinman.. 08/27/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 27 12:40:36 2026

ACUS01 KWNS 271240
SWODY1
SPC AC 271238

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 AM CDT Thu Aug 27 2026

Valid 271300Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC/NORTHEAST...AND THE CENTRAL PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Northeast and Mid-Atlantic today. Damaging winds, severe
hail, and a tornado or two may accompany these thunderstorms. Large
to very large hail and severe gusts are also possible across parts
of southwest South Dakota into western/central Nebraska and
northwest Kansas.

...Mid-Atlantic/Northeast...
An elongated mid/upper-level trough with closed low over Hudson Bay
will encompass much of the eastern CONUS today. Embedded within this large-scale troughing, a mid-level shortwave trough with modestly
enhanced southwesterly winds (around 25-35 kt) will advance
northeastward through the day across the Mid-Atlantic and Northeast.
At the surface, a weak low over eastern Ontario will develop into
Quebec this afternoon, with a trailing cold front advancing
southeastward across the Mid-Atlantic/Northeast through the period.
Stronger daytime heating is forecast with southward extent across
the Mid-Atlantic ahead of the cold front, with cloud cover
potentially limiting heating somewhat across the Northeast. Even so,
a zone of moderate instability should develop by this afternoon
across these regions, with sufficient deep-layer shear for some
updraft organization. Current expectations are for thunderstorms to
gradually increase in coverage and intensity by 17-20Z ahead of the
surface front and a lee trough along/east of the Appalachians. A mix
of multicells and supercells should pose a threat for both severe
hail and damaging winds, especially from the northern Mid-Atlantic
northward into NY and vicinity. A tornado or two may also occur,
with modest hodograph curvature noted in various NAM/RAP forecast
soundings from northern MD northeastward to western New England.

...Central Plains...
The central Plains will be sandwiched between upper ridging over the
Southwest and upper troughing over eastern Canada today, with modest northwesterly flow aloft persisting through the period. Large-scale
ascent is forecast to remain rather weak/nebulous, with some
guidance suggesting a weak mid-level impulse will crest the ridge
and aid convective initiation across parts of southwest SD into
western/central NE this afternoon. A corridor of greater low-level
moisture (generally 60s surface dewpoints) will be in place across
this region. Daytime heating of this moist airmass coupled with the
presence of steep mid-level lapse rates will help foster moderate to
locally strong instability and erode lingering MLCIN by 19-21Z.
While robust convective development and overall coverage still
remains somewhat uncertain given the weak forcing, a rather
favorable environment for supercells will exist. Any sustained
supercells will be capable of producing large hail (some 2+ inches)
as they track south-southeastward through the late afternoon into
the evening. The potential for severe/damaging gusts is also
uncertain, as most guidance does not show a cluster developing this
evening. An isolated threat for severe hail/gusts may also exist
farther west/south across the CO Front Range to Raton Mesa vicinity,
although deep-layer shear should be weaker across these areas.

...Northern Rockies/High Plains...
A mid-level jet on the southeast periphery of upper troughing over
the eastern Pacific and western Canada will translate northeastward
across the northern Rockies today. Enhanced west-southwesterly flow
and lift associated with this jet will likely aid isolated to
scattered thunderstorm development this afternoon across parts of
the northern Rockies, with this activity spreading into the adjacent
High Plains through the evening. While low-level moisture will
remain limited/shallow across these regions, steep low/mid-level
lapse rates amid a well-mixed boundary layer coupled with moderate
to strong deep-layer shear should support a threat for isolated
severe gusts with the high-based convection that develops.

...Great Basin...
High-based thunderstorms should also develop this afternoon across
portions of northeast NV into northwest UT and southeast ID. While low/mid-level winds and related thunderstorm organization will
likely be somewhat weaker/limited compared to areas farther north,
steep lapse rates and large DCAPE will support potential for strong
to severe outflow gusts as this convection spreads northeastward
into the early evening.

...South-Central/Coastal Texas into Southern Louisiana...
Ongoing thunderstorms across southern LA may pose a threat for gusty
winds this morning before they move offshore. Additional
thunderstorms may develop this afternoon from parts of south-central
TX towards the upper TX Coast, with isolated severe/damaging
downburst winds possible given ample moisture/instability forecast.
Weak deep-layer shear should limit the overall severe threat.

..Gleason/Broyles.. 08/27/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 27 16:26:00 2026

ACUS01 KWNS 271625
SWODY1
SPC AC 271624

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CDT Thu Aug 27 2026

Valid 271630Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC/NORTHEAST...THE CENTRAL PLAINS...AND CENTRAL
MONTANA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Northeast and Mid-Atlantic today. Damaging winds, severe
hail, and a tornado or two may accompany these thunderstorms. Large
to very large hail and severe gusts are also possible across parts
of northern High Plains and central Plains.

...Mid-Atlantic/Northeast...
Recent surface analysis places a low over western Quebec, with a
cold front arcing from this low southwestward through the middle OH
Valley, western TN Valley and then westward across central AR and
central OK. Satellite imagery reveals a shortwave trough extending
from northeastern Ontario through western PA, just west of the
analyzed surface low. There also appears to be a more subtle
shortwave trough farther south moving through WV towards VA.

Expectation is for the primary shortwave trough and cold front to
continue eastward, interacting with the very moist airmass across
the Northeast to support thunderstorm development this afternoon.
12Z ILN and PIT soundings sampled the moderate westerly flow aloft,
supporting the potential for strong multicells along both the cold
front and pre-frontal troughing. A few supercells are possible if
warm sector development can mature without too much interaction with
other convection. Primary risk will be damaging gusts, although the
modestly cool temperatures aloft (i.e. -10 to -12 deg C at 500-mb)
suggest some hail is possible as well.

A somewhat displaced area of earlier thunderstorm development is
manifesting across the northern Mid-Atlantic. As mentioned in MCD
#2145, a broken band of thunderstorms is ongoing as of mid-morning
from the New York City vicinity southwest toward Baltimore, with
that activity potentially being aided by forcing for ascent
associated with the subtle shortwave trough moving into VA. Airmass
across this region is very moist, and instability is steadily
building under modest diurnal heating. Most guidance suggests this
activity gradually increases in coverage and intensity over the next
few hours. The presence of a vertically veering wind profile
with around 30 to 35 kt of effective bulk shear would support a
conditional risk for embedded supercell structures capable of
locally damaging winds, marginally severe hail, and perhaps a brief
tornado.

...Northern Rockies/High Plains...
Recent satellite imagery depicts a shortwave trough progressing
across eastern OR towards ID and western MT. Moderate mid-level
moisture and forcing for ascent associated with this wave are
forecast to initiate thunderstorms across the northern Rockies this
afternoon. This activity is then forecast to progress northeastward
off the higher terrain into central MT, where a deeply mixed airmass
is forecast to be in place. Despite this deep mixing and somewhat
limited low-level moisture, the mid-level moisture associated with
the shortwave will allow for at least modest buoyancy (i.e. MLCAPE
over 500 J/kg). This should support storm maintenance off the
terrain, with a trend towards outflow-dominant bowing segments with
time. Primary severe risk is damaging gusts, including the potential
for gusts from 65 to 75 mph.

...Central Plains...
Moist southerly flow will help maintain moderate low-level moisture
through the NE Panhandle and into southwest SD amid the strong
heating and boundary-layer mixing expected this afternoon.
Additionally, this modest, but persistent, warm-air advection is
likely to force convective initiation this afternoon over the
western NE/SD border vicinity. Low-level southerly flow veering to
moderate northwesterlies aloft will support deep-layer shear of 40
to 50 kt, more than adequate for supercell development with any
mature convective. Any sustained supercells will be capable of
producing large hail (some 2+ inches) as they track
south-southeastward through the late afternoon into the evening.
Upscale growth into one or more bowing segments appears likely this
evening, with strong to severe gusts (65 to 75 mph) possible.

An isolated threat for severe hail/gusts may also exist
farther west/south across the CO Front Range to Raton Mesa vicinity.
Weaker buoyancy and deep-layer shear should keep any more organized
updrafts confined to the higher terrain and Foothills.

-- No other changes needed to the outlook with the text for the
additional areas appended from the 13Z Outlook below --

...Great Basin...
High-based thunderstorms should also develop this afternoon across
portions of northeast NV into northwest UT and southeast ID. While low/mid-level winds and related thunderstorm organization will
likely be somewhat weaker/limited compared to areas farther north,
steep lapse rates and large DCAPE will support potential for strong
to severe outflow gusts as this convection spreads northeastward
into the early evening.

...South-Central/Coastal Texas into Southern Louisiana...
Ongoing thunderstorms across southern LA may pose a threat for gusty
winds this morning before they move offshore. Additional
thunderstorms may develop this afternoon from parts of south-central
TX towards the upper TX Coast, with isolated severe/damaging
downburst winds possible given ample moisture/instability forecast.
Weak deep-layer shear should limit the overall severe threat.

..Mosier/Chalmers.. 08/27/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 27 19:52:58 2026

ACUS01 KWNS 271952
SWODY1
SPC AC 271951

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Thu Aug 27 2026

Valid 272000Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC/NORTHEAST...CENTRAL PLAINS...AND CENTRAL MONTANA...

...SUMMARY...
Scattered strong to severe thunderstorms remain possible across
parts of the Northeast and Mid-Atlantic today. Damaging winds,
severe hail, and a tornado or two may accompany these thunderstorms.
Large to very large hail and severe gusts are also possible across
parts of northern High Plains and central Plains.

...20z Update...

The forecast remains on track with only minor changes made to the
existing outlook. See the discussion below as well as MCDs 2148,
2149, and 2150 for additional details.

..Chalmers/Thornton.. 08/27/2026

.PREV DISCUSSION... /ISSUED 1124 AM CDT Thu Aug 27 2026/

...Mid-Atlantic/Northeast...
Recent surface analysis places a low over western Quebec, with a
cold front arcing from this low southwestward through the middle OH
Valley, western TN Valley and then westward across central AR and
central OK. Satellite imagery reveals a shortwave trough extending
from northeastern Ontario through western PA, just west of the
analyzed surface low. There also appears to be a more subtle
shortwave trough farther south moving through WV towards VA.

Expectation is for the primary shortwave trough and cold front to
continue eastward, interacting with the very moist airmass across
the Northeast to support thunderstorm development this afternoon.
12Z ILN and PIT soundings sampled the moderate westerly flow aloft,
supporting the potential for strong multicells along both the cold
front and pre-frontal troughing. A few supercells are possible if
warm sector development can mature without too much interaction with
other convection. Primary risk will be damaging gusts, although the
modestly cool temperatures aloft (i.e. -10 to -12 deg C at 500-mb)
suggest some hail is possible as well.

A somewhat displaced area of earlier thunderstorm development is
manifesting across the northern Mid-Atlantic. As mentioned in MCD
#2145, a broken band of thunderstorms is ongoing as of mid-morning
from the New York City vicinity southwest toward Baltimore, with
that activity potentially being aided by forcing for ascent
associated with the subtle shortwave trough moving into VA. Airmass
across this region is very moist, and instability is steadily
building under modest diurnal heating. Most guidance suggests this
activity gradually increases in coverage and intensity over the next
few hours. The presence of a vertically veering wind profile
with around 30 to 35 kt of effective bulk shear would support a
conditional risk for embedded supercell structures capable of
locally damaging winds, marginally severe hail, and perhaps a brief
tornado.

...Northern Rockies/High Plains...
Recent satellite imagery depicts a shortwave trough progressing
across eastern OR towards ID and western MT. Moderate mid-level
moisture and forcing for ascent associated with this wave are
forecast to initiate thunderstorms across the northern Rockies this
afternoon. This activity is then forecast to progress northeastward
off the higher terrain into central MT, where a deeply mixed airmass
is forecast to be in place. Despite this deep mixing and somewhat
limited low-level moisture, the mid-level moisture associated with
the shortwave will allow for at least modest buoyancy (i.e. MLCAPE
over 500 J/kg). This should support storm maintenance off the
terrain, with a trend towards outflow-dominant bowing segments with
time. Primary severe risk is damaging gusts, including the potential
for gusts from 65 to 75 mph.

...Central Plains...
Moist southerly flow will help maintain moderate low-level moisture
through the NE Panhandle and into southwest SD amid the strong
heating and boundary-layer mixing expected this afternoon.
Additionally, this modest, but persistent, warm-air advection is
likely to force convective initiation this afternoon over the
western NE/SD border vicinity. Low-level southerly flow veering to
moderate northwesterlies aloft will support deep-layer shear of 40
to 50 kt, more than adequate for supercell development with any
mature convective. Any sustained supercells will be capable of
producing large hail (some 2+ inches) as they track
south-southeastward through the late afternoon into the evening.
Upscale growth into one or more bowing segments appears likely this
evening, with strong to severe gusts (65 to 75 mph) possible.

An isolated threat for severe hail/gusts may also exist
farther west/south across the CO Front Range to Raton Mesa vicinity.
Weaker buoyancy and deep-layer shear should keep any more organized
updrafts confined to the higher terrain and Foothills.

-- No other changes needed to the outlook with the text for the
additional areas appended from the 13Z Outlook below --

...Great Basin...
High-based thunderstorms should also develop this afternoon across
portions of northeast NV into northwest UT and southeast ID. While low/mid-level winds and related thunderstorm organization will
likely be somewhat weaker/limited compared to areas farther north,
steep lapse rates and large DCAPE will support potential for strong
to severe outflow gusts as this convection spreads northeastward
into the early evening.

...South-Central/Coastal Texas into Southern Louisiana...
Ongoing thunderstorms across southern LA may pose a threat for gusty
winds this morning before they move offshore. Additional
thunderstorms may develop this afternoon from parts of south-central
TX towards the upper TX Coast, with isolated severe/damaging
downburst winds possible given ample moisture/instability forecast.
Weak deep-layer shear should limit the overall severe threat.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 28 01:11:08 2026

ACUS01 KWNS 280110
SWODY1
SPC AC 280109

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0809 PM CDT Thu Aug 27 2026

Valid 280100Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
WEST-CENTRAL NE INTO NORTHWEST KS...NORTHERN MID-ATLANTIC...AND
WEST-CENTRAL MT...

...SUMMARY...
Storms capable of producing severe hail and wind remain possible
this evening across west-central Nebraska into northwest Kansas.
Localized wind damage also remains possible over parts of the
Mid-Atlantic and Northeast. Storms with localized severe gusts will
continue through the evening across west-central Montana.

...Central Plains...
Earlier supercells have congealed into a small southward-moving
cluster across northwest NE. Steep lapse rates, strong buoyancy
(MLCAPE of 2000-3000 J/kg) and effective shear of 40-50 kt (as
observed on the 00Z LBF sounding) within a northwesterly flow regime
will continue to support organized storms through the evening. The
severe-wind (potentially exceeding 75 mph) threat associated with
this small MCS is expected to spread towards parts of southwest NE
and northwest KS. Any embedded supercells or discrete cells along
the periphery of the cluster will also remain capable of producing
large hail, given the favorable thermodynamic environment and
relatively elongated hodographs. Longevity of this cluster into late
tonight is uncertain, due to increasing MLCINH and generally modest
large-scale ascent. Some severe potential could spread as far as west-central/southwest KS before diminishing.

...Parts of the Mid-Atlantic/Northeast...
Scattered strong to locally severe storms are ongoing this evening
from the northern Mid-Atlantic into parts of the Northeast. While
substantial convective overturning has occurred, a corridor of
moderate MLCAPE remains in place from northern VA into eastern PA
and southeast NE. A short-term threat for locally damaging wind and
perhaps marginal hail may continue before storms generally weaken by
late evening. See MCD 2157 for more information.

...West-central MT...
High-based convection is ongoing early this evening across parts of west-central MT. Weak buoyancy will continue to hamper storm
intensity, but the favorable lapse rate environment will continue to
support potential for strong to severe gusts. See MCD 2158 for more information.

...Parts of south-central TX...
Scattered storms across south-central TX are ongoing near a
southward-moving composite outflow. These storms may be capable of
producing localized damaging gusts through dusk, before weakening
with the onset of nocturnal cooling/stabilization.

..Dean.. 08/28/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 28 06:02:20 2026

ACUS01 KWNS 280601
SWODY1
SPC AC 280600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Aug 28 2026

Valid 281200Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL/NORTHERN PLAINS...GREAT BASIN AND DESERT SOUTHWEST INTO THE
NORTHERN ROCKIES...NORTH GA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN ME...

...SUMMARY...
Isolated strong to severe storms are possible across the central and
northern Plains, northern Georgia into the Carolinas and
Mid-Atlantic, central and eastern Maine, and from parts of the Great
Basin and Desert Southwest into the northern Rockies.

...Central/northern Plains westward into the northern
Rockies...Great Basin...and Desert Southwest...
An upper ridge will remain anchored over parts of the
Southwest/southern Rockies today. A series of midlevel vorticity
maxima will move along the periphery of the ridge from central CA
into the Great Basin, northern Rockies, and northern Plains.

Across the central/northern Plains, moderate to locally strong
destabilization is forecast along/east of a surface trough that will
extend from the western Dakotas into the NE Panhandle. Relatively
strong MLCINH may limit coverage of diurnal storm development near
this surface trough, but deep-layer shear will support a hail and
localized severe-wind threat with any sustained storms through early
evening. A greater coverage of elevated convection is expected to
develop later this evening into the overnight, as storms spread
toward the eastern Dakotas and southwest MN. The pattern generally
suggests potential MCS development, though most CAM guidance is
relatively subdued regarding the intensity and attendant severe-wind
threat associated with the late-night storms. Greater severe
probabilities may eventually be needed, if confidence increases
regarding development of diurnal storms and/or a robust nocturnal
MCS.

Farther west, relatively widespread storm development is expected
from the Great Basin into the northern Rockies, potentially aided by
the midlevel vorticity maxima traversing the region. Buoyancy will
generally remain weak, but steep lapse rates and increasing flow in
the 700-500 mb layer along the periphery of the ridge will support
potential for persistent outflow-driven cells/clusters and strong to
localized severe gusts across a broad region.

...Carolinas/north GA into the Mid-Atlantic...
A relatively broad/weak upper trough will gradually shift eastward
today across parts of the Southeast, Carolinas, and Mid-Atlantic.
Widely scattered storm development is expected this afternoon within
a weakly capped and moderately buoyant environment. Relatively steep
low-level lapse rates and large PW will support localized downburst
potential, though weak deep-layer shear should generally limit the organized-severe threat.

...Parts of Maine...
Scattered thunderstorms are expected to develop along/ahead of a
weak surface trough/front across parts of Maine this afternoon.
Modest destabilization (with MLCAPE approaching 1000 J/kg) and
marginally supportive deep-layer shear could support at least
transient storm organization. The environment will not be
particularly favorable for severe wind or hail, but guidance
suggests some eventual clustering of storms and potential for
isolated wind damage and small to near-severe hail across parts of
central and eastern ME from the afternoon into the early evening.

..Dean/Wendt.. 08/28/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 28 12:33:12 2026

ACUS01 KWNS 281232
SWODY1
SPC AC 281231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Fri Aug 28 2026

Valid 281300Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL/NORTHERN PLAINS...GREAT BASIN AND DESERT SOUTHWEST INTO THE
NORTHERN ROCKIES...NORTH GA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN ME......

...SUMMARY...
Isolated strong to severe storms are possible across the central and
northern Plains, northern Georgia into the Carolinas and
Mid-Atlantic, central and eastern Maine, and from parts of the Great
Basin and Desert Southwest into the northern Rockies.

...Maine...
A shortwave trough is evident this morning over the St Lawrence
Valley. This trough will track eastward across northern New
England, with an associated cold front moving through ME. Models
are consistent in the depiction of scattered thunderstorm
development along the front by mid-late afternoon. Forecast
soundings show sufficient CAPE and deep layer shear to promote a few
organized or potentially supercell storms capable of locally
damaging wind gusts and hail.

...GA to Mid-Atlantic Region...
Broad cyclonic flow aloft will be present today over much of the
eastern states, with a diffuse surface cold front extending from VA
into GA. Widely scattered thunderstorms are expected to form along
the front this afternoon, with slow-moving but strong storms
possible. Moderate CAPE, rather high PWAT values, and limited
deep-layer shear will promote isolated strong storms capable of
water-loaded downbursts.

...Great Basin into WY...
The upper ridge will remain centered over NM, while a 50+ knot
mid-level jet rotates eastward from NV into ID/UT/WY. Scattered
high-based showers and storms are expected over a large part of the
Great Basin into WY, with the strongest cells capable of damaging
wind gusts.

...Dakotas...
As the high-based convection over WY spreads eastward into western
ND/SD, it will encounter greater low-level moisture and CAPE, likely
resulting in some intensification. A few bowing structures are
possible in this area this evening, capable of locally damaging wind
gusts and hail. This complex of storms may persist after midnight
with a continued risk of gusty/damaging winds.

..Hart/Kerr.. 08/28/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 28 16:32:12 2026

ACUS01 KWNS 281632
SWODY1
SPC AC 281630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Fri Aug 28 2026

Valid 281630Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL/NORTHERN PLAINS...GREAT BASIN AND DESERT SOUTHWEST INTO THE
NORTHERN ROCKIES...NORTH GA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN ME......

...SUMMARY...
Isolated strong to severe storms are possible across the central and
northern Plains, northern Georgia into the Carolinas and
Mid-Atlantic, central and eastern Maine, and from parts of the Great
Basin and Desert Southwest into the northern Rockies.

...Maine...
Morning surface analysis places a low over eastern Quebec, with a
cold front extending southward from this low through northern NY
before arcing more southwestward and becoming increasingly diffuse
across the Upper OH Valley. A shortwave trough is forecast to
progress through southern Quebec towards the St. Lawrence Valley
today. The surface low is forecast to eject northeastward in
response, with its attendant cold front sweeping eastward across ME.
A moist airmass precedes this front, with current observations
sampling mid to upper 60s dewpoints. This airmass should destabilize
amid filtered daytime heating ahead of the front, although poor
mid-level lapse will limit the overall buoyancy. Scattered
thunderstorm development is anticipated as the cold front interacts
with this modestly buoyant airmass. A few strong to severe storms
are possible, but deep-layer shear largely parallel to the frontal
boundary will contribute to a predominantly linear mode and a likely
trend toward undercutting of new updrafts. Even so, any updrafts
that can mature could organize, potentially becoming supercell
storms capable of locally wind gusts and hail.

...Mid-Atlantic into Georgia...
Morning surface analysis places a low off the southern New England
coast and another over southern NJ (near the ongoing thunderstorms).
A weak front extends through these two lows, continuing
southwestward across the Carolina Piedmont into northern GA. Widely
scattered thunderstorms are expected to form along
the front this afternoon, with slow-moving but strong storms
possible. The stronger (but still modest) deep-layer shear will
occur across VA and NC, with the stronger buoyancy displaced farther
south across SC and GA. Even so, the expectation is that a
combination of moderate CAPE, high PWAT values, and limited
deep-layer shear will promote isolated strong storms capable of
water-loaded downbursts.

...Great Basin through Wyoming..
A belt of stronger mid-level flow currently extends from central CA
through the northern Rockies between the upper troughing over
western Canada and the upper ridging centered over the Four Corners. Low-amplitude shortwave troughs embedded within this enhanced flow,
and associated ascent and mid-level moisture, will contribute to
thunderstorm development this afternoon. A deeply mixed boundary
layer is anticipated throughout much of this region, suggesting any
of the stronger, more persistent storms could produce damaging
gusts. Highest storm coverage is expected from eastern NV into
central/northern UT, resulting in a relatively greater threat for
damaging gusts within this corridor.

...Dakotas into western Minnesota and northern Iowa...
There could potentially be two rounds of convection across the
northern Plains today. The first will be with any of the high-based
convection from WY as it spreads eastward into western
Dakotas, where greater low-level moisture and buoyancy will be in
place. The greater buoyancy could result in reintensification and a
few bowing structures capable of producing locally damaging wind
gusts and hail.

Additional warm-air advection associated development is then
possible later this evening as the low-level jet strengthens over
the Plains. These elevated storms should develop within an
environment characterized by moderate buoyancy and deep-layer shear,
suggesting a few supercells capable of large hail are possible
initially. Over time, some upscale growth is possible, which could
result in a low-probability risk for damaging gusts over southwest
MN and adjacent northwest IA early tomorrow morning.

..Mosier/Moore.. 08/28/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 28 19:44:12 2026

ACUS01 KWNS 281944
SWODY1
SPC AC 281942

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 PM CDT Fri Aug 28 2026

Valid 282000Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL/NORTHERN PLAINS...GREAT BASIN AND DESERT SOUTHWEST INTO THE
NORTHERN ROCKIES...NORTH GEORGIA INTO THE CAROLINAS AND
MID-ATLANTIC...AND PARTS OF CENTRAL/EASTERN MAINE...

...SUMMARY...
Isolated strong to severe storms are possible across the central and
northern Plains, northern Georgia into the Carolinas and
Mid-Atlantic, central and eastern Maine, and from parts of the Great
Basin and Desert Southwest into the northern Rockies.

...20z Update...
The previous forecast largely remains on track with only minor edits
required - primarily to the general thunder line to reflect recent
convective trends. Weak/poorly organized convection ongoing across
the Mid-Atlantic and portions of Maine should continue to pose a
localized severe threat (mainly damaging wind) through late
afternoon. See MCDs #2162 and #2163 for additional short-term
details. Transient downbursts have been noted across the greater
Houston, TX area over the past 1-2 hours as thunderstorms develop
along the sea breeze. While small swaths of damaging wind may occur
with the more intense downbursts, this threat is expected to remain
fairly transient given poor deep-layer wind shear across the region
(wind speeds are generally 15 knots or less through the column per
regional VWPs).

Across the Great Basin, slight expansions of the 5% wind
probabilities were made to better reflect trends in recent
time-lagged CAM guidance. Some of the more aggressive solutions -
notably recent runs of the RRFS - hint at one or more corridors of
higher severe wind potential across eastern WY into SD as high-based
convection encounters richer low-level moisture/buoyancy over the
Plains. However, these solutions are exhibiting a considerable warm
bias compared to current observations and suggest that any residual
inhibition should be mixed out by this point in the day. Latest GOES
imagery and regional 18z soundings both depict lingering inhibition,
which casts considerable uncertainty onto the accuracy of the more
aggressive solutions.

..Moore.. 08/28/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 28 2026/

...Maine...
Morning surface analysis places a low over eastern Quebec, with a
cold front extending southward from this low through northern NY
before arcing more southwestward and becoming increasingly diffuse
across the Upper OH Valley. A shortwave trough is forecast to
progress through southern Quebec towards the St. Lawrence Valley
today. The surface low is forecast to eject northeastward in
response, with its attendant cold front sweeping eastward across ME.
A moist airmass precedes this front, with current observations
sampling mid to upper 60s dewpoints. This airmass should destabilize
amid filtered daytime heating ahead of the front, although poor
mid-level lapse will limit the overall buoyancy. Scattered
thunderstorm development is anticipated as the cold front interacts
with this modestly buoyant airmass. A few strong to severe storms
are possible, but deep-layer shear largely parallel to the frontal
boundary will contribute to a predominantly linear mode and a likely
trend toward undercutting of new updrafts. Even so, any updrafts
that can mature could organize, potentially becoming supercell
storms capable of locally wind gusts and hail.

...Mid-Atlantic into Georgia...
Morning surface analysis places a low off the southern New England
coast and another over southern NJ (near the ongoing thunderstorms).
A weak front extends through these two lows, continuing
southwestward across the Carolina Piedmont into northern GA. Widely
scattered thunderstorms are expected to form along
the front this afternoon, with slow-moving but strong storms
possible. The stronger (but still modest) deep-layer shear will
occur across VA and NC, with the stronger buoyancy displaced farther
south across SC and GA. Even so, the expectation is that a
combination of moderate CAPE, high PWAT values, and limited
deep-layer shear will promote isolated strong storms capable of
water-loaded downbursts.

...Great Basin through Wyoming..
A belt of stronger mid-level flow currently extends from central CA
through the northern Rockies between the upper troughing over
western Canada and the upper ridging centered over the Four Corners. Low-amplitude shortwave troughs embedded within this enhanced flow,
and associated ascent and mid-level moisture, will contribute to
thunderstorm development this afternoon. A deeply mixed boundary
layer is anticipated throughout much of this region, suggesting any
of the stronger, more persistent storms could produce damaging
gusts. Highest storm coverage is expected from eastern NV into
central/northern UT, resulting in a relatively greater threat for
damaging gusts within this corridor.

...Dakotas into western Minnesota and northern Iowa...
There could potentially be two rounds of convection across the
northern Plains today. The first will be with any of the high-based
convection from WY as it spreads eastward into western
Dakotas, where greater low-level moisture and buoyancy will be in
place. The greater buoyancy could result in reintensification and a
few bowing structures capable of producing locally damaging wind
gusts and hail.

Additional warm-air advection associated development is then
possible later this evening as the low-level jet strengthens over
the Plains. These elevated storms should develop within an
environment characterized by moderate buoyancy and deep-layer shear,
suggesting a few supercells capable of large hail are possible
initially. Over time, some upscale growth is possible, which could
result in a low-probability risk for damaging gusts over southwest
MN and adjacent northwest IA early tomorrow morning.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 29 01:00:46 2026

ACUS01 KWNS 290100
SWODY1
SPC AC 290058

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 PM CDT Fri Aug 28 2026

Valid 290100Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
BASIN...TO THE CENTRAL ROCKIES AND NORTHERN PLAINS...

...SUMMARY...
Isolated strong to severe storms are possible across the northern
Plains, and from parts of the Great Basin and Desert Southwest into
the Rockies.

...Great Basin/Rockies...
Evening water vapor imagery showed an expansive area of high
pressure centered over the Four Corners with broad southwesterly
flow aloft ongoing over much of the Great Basin and Rockies. To the
west of the ridge, an upper low and broad trough were moving onshore
across the Pacific Northwest and CA respectively. Ahead of these
features, several weaker perturbations and a plume of mid-level
moisture were contributing to widely scattered thunderstorms over
the Great Basin and central Rockies this evening.

Despite limited buoyancy owing to expansive cloud cover, plentiful
monsoon moisture should continue to support widely scattered
high-based thunderstorms this evening and into the overnight hours.
At least isolated strong to severe gusts are possible owing to dry
low-levels suitable for strong downdrafts with the established
storms/clusters. This appears most likely from far eastern NV,
across northern UT, and into central WY where the air mass remains
the warmest.

...Northern Plains...
The first of the mid-level shortwave troughs embedded within the
broader southwest flow are expected to eject eastward over the
northern Plains tonight. As ascent from the wave overspreads a warm
front, the low-level jet is forecast to strengthen (40-50 kt),
supporting a broad area of low-level warm air advection across the
eastern Dakotas into MN/IA. Elevated storms should develop near the
front with moderate buoyancy and deep-layer shear supportive of
supercells. Some hail risk is possible with these storms overnight.
Given the increasing forcing for ascent, upscale growth into a
cluster or MCS is possible, which could result in a low-probability
risk for damaging gusts over southwest MN and adjacent northwest IA
through 12z Saturday.

...Mid Atlantic to the Southeast...
Several clusters of scattered thunderstorms remain ongoing ahead of
a weak front from VA to the northern Gulf Coast. These storms have
slowly weakened through the evening and should continue to do so
with the loss of diurnal heating. Ahead of the front, high PWAT
content (2-2.5 inches) may still support a sporadic downbursts with
the stronger clusters this evening. However, weak shear and waning
diurnal buoyancy suggest an organized or expansive severe threat is
unlikely.

..Lyons.. 08/29/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 29 05:56:46 2026

ACUS01 KWNS 290556
SWODY1
SPC AC 290554

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Sat Aug 29 2026

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
EASTERN NEVADA...NORTHERN UTAH...AND SOUTHWEST WYOMING...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin and northern/central Rockies. Severe
wind gusts are the main threat. Isolated severe storms are also
possible across portions of the northern Plains, with potential for
large hail and damaging wind.

...Great Basin/Rockies...
An upper low over the Pacific Northwest is forecast to merge with a
broad southern steam upper trough over the Great Basin. A belt of
enhanced mid-level flow and tropical moisture will overspread the
Great Basin and central Rockies. Clouds, showers and some
thunderstorms are likely to be ongoing early in the period
complicating expectations for diurnal heating and subsequent
destabilization. Still, filtered heating should allow for additional
storms to develop through the day along a weak front and across the
higher terrain from eastern NV into northern UT and the central
Rockies. Sufficiently strong unidirectional effective shear profiles
and a well-mixed boundary layer will promote a few organized
clusters and potentially transient supercell structures capable of
severe wind gusts and marginally severe hail.

...Four Corners...
On the southern fringes of upper trough moving through the Great
Basin, strong heating of a monsoon air mass should allow for the
development of scattered to numerous thunderstorms across northern
AZ and southern UT. Deep-layer flow here will be considerably weaker
compared to points farther north, but sight enhancement could still
support some clustering of thunderstorms. Steep low/mid-level lapse
rates, PWATs over 1 inch and numerous storms may bolster downdrafts.
Isolated severe gusts are possible as storms spread eastward into
southwestern CO and NM through the afternoon/evening.

...Northern Plains..
Several embedded disturbances within the enhanced southwesterly flow
aloft will help deepen a lee trough/low across eastern WY and
western SD this afternoon. Strengthening southerly upslope flow will
advect upper 60s F dewpoints into the region aiding in moderate destabilization. However, widespread mid/upper-level cloud cover and
weak overall forcing for ascent cast some uncertainty on storm
development through the afternoon. If storms do develop, moderate
buoyancy and elongated mid/upper-level hodographs would support
supercells with the potential for damaging winds and hail.

The more likely scenario is that high-based convection emanating
from central WY will spread eastward late in the afternoon/early
evening with the potential for isolated damaging gusts. Some
intensification of this convection may occur as it encounters the
more unstable air mass into the overnight hours, though CAM
solutions are varied.

...IA/MN...
A remnant cluster of storms or a weakly organized MCS is likely to
be ongoing at the start of the period along the front from
southwestern MN into northern IA. Driven by strong overnight warm
advection at the terminus of the low-level jet, weak buoyancy, but
relatively strong deep-layer shear could support an isolated risk
for hail or damaging gusts for a couple of hours during the morning.
Weakening ascent and increasing mid-level heights should limit the
severe risk through the remainder of the day.

...Atlantic Coast...
Scattered thunderstorms are likely along typical sea breeze
boundaries and a weakening front from the Carolinas to FL this
afternoon. An unstable, high PWAT, but very weakly sheared air mass
will support multicell storms with sporadic wet microburst
potential. However, confidence in a more widespread or organized
severe risk remains below 5%.

..Lyons/Wendt.. 08/29/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 29 12:19:22 2026

ACUS01 KWNS 291219
SWODY1
SPC AC 291217

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0717 AM CDT Sat Aug 29 2026

Valid 291300Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN
NEVADA INTO NORTHERN UTAH...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and northern
Plains. Severe wind gusts are the main threat.

...Great Basin into Central/Northern Rockies...
A broad upper trough is present today across the Southern Rockies
into OK/TX, with relatively fast flow aloft extending from NV into
WY. IR satellite imagery suggests considerable cloud cover is
affecting much of the Great Basin region, which will limit daytime heating/destabilization and overall severe threat. Nevertheless,
there appears to be a corridor from eastern NV across parts of
north-central UT where sufficient heating will result in steep
low-level lapse rates and favorable CAPE profiles for a few
high-based thunderstorms capable of damaging wind gusts. Supercell
structures are also possible in this corridor, suggesting a risk of
hail in the strongest storms.

...Northern Plains...
Similar to yesterday, clusters of high-based showers and
thunderstorms will spread eastward across WY into parts of the
Dakotas/NE this afternoon and evening. Favorable winds aloft,
combined with at least marginal CAPE will aid in a risk of locally
damaging wind gusts and hail.

..Hart/Broyles.. 08/29/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 29 16:31:18 2026

ACUS01 KWNS 291631
SWODY1
SPC AC 291629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat Aug 29 2026

Valid 291630Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN
NEVADA ACROSS NORTHERN UTAH INTO FAR SOUTHWEST WYOMING...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and northern
Plains. Severe wind gusts are the main threat.

...Great Basin through the central Rockies...
Enhanced mid-level southwesterly flow aloft exists between the upper
ridging centered over the southern High Plains and a shortwave
trough moving through the Pacific Northwest. 12Z SLC sounding
sampled this enhanced flow well, reporting a belt of 50-55 kt wind
around 600 to 500 mb. This sounding also sampled the increased
mid-level moisture within this belt of stronger flow, resulting
precipitable water over 1.1".

Modest heating of this airmass is expected to foster moderate
buoyancy, although the widespread cloudiness could keep the airmass
from fully destabilizing. Most RAP soundings across the region
maintain lingering convective inhibition from UT into southern WY.
Even so, the combination of modest buoyancy, mid-level moisture, and
ascent attendant to a low-amplitude shortwave trough progressing
through the region will support scattered to numerous thunderstorms
from eastern NV across UT into northwest CO/southern WY. Some
isolated hail is possible with the strongest cores (which could
briefly acquire supercellular characteristics), but the primary
severe risk is strong to severe wind gusts. Highest severe coverage
is still expected from east-central NV into northern UT where the
greatest afternoon buoyancy is forecast.

...Northeast CO/eastern WY/NE Panhandle into the western/central
Dakotas...
High-based showers and thunderstorms along the leading edge of the
strongest ascent attendant to the shortwave trough moving through
the Great Basin and central Rockies should emerge into a diurnally
destabilized and moderately buoyant airmass from northeast CO into
eastern WY and the NE Panhandle during the late afternoon/early
evening. This could result in reintensification, and a risk for both
large hail and damaging gusts across the region throughout the
evening. Most of the guidance was overly aggressive with
destabilization and buoyancy across this region yesterday, and there
is some concern that cloud cover could again limit heating. That
being said, there is a pocket of greater low-level moisture across
SD and the region is currently under widely scattered cloud cover.
Enhanced westerly flow atop low-level easterlies will support at
least moderate deep-layer shear, so any updrafts that can mature
should be able to organize, with an attendant risk for large hail
and damaging gusts.

...AZ...
12Z PHX sounding sampled moderate mid-level moisture atop warm and
dry low levels. Scattered thunderstorm development is anticipated
across much of the region. Vertical shear is weak and a largely
disorganized storm mode is anticipated. Still, given the high storm
bases and steep low-level lapse rates, isolated strong to severe
gusts are possible this afternoon and evening.

..Mosier/Moore.. 08/29/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sat Aug 29 19:50:50 2026

ACUS01 KWNS 291950
SWODY1
SPC AC 291949

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 PM CDT Sat Aug 29 2026

Valid 292000Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEVERE
THUNDERSTORMS FROM EASTERN NEVADA ACROSS NORTHERN UTAH INTO FAR
SOUTHWEST WYOMING...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and northern
Plains. Severe wind gusts are the main threat.

...20z Update...
No changes are needed to the current D1 Convective Outlook. See MCDs
#2167, #2168, and the previous discussion below for more
information.

..Thornton.. 08/29/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 29 2026/

...Great Basin through the central Rockies...
Enhanced mid-level southwesterly flow aloft exists between the upper
ridging centered over the southern High Plains and a shortwave
trough moving through the Pacific Northwest. 12Z SLC sounding
sampled this enhanced flow well, reporting a belt of 50-55 kt wind
around 600 to 500 mb. This sounding also sampled the increased
mid-level moisture within this belt of stronger flow, resulting
precipitable water over 1.1".

Modest heating of this airmass is expected to foster moderate
buoyancy, although the widespread cloudiness could keep the airmass
from fully destabilizing. Most RAP soundings across the region
maintain lingering convective inhibition from UT into southern WY.
Even so, the combination of modest buoyancy, mid-level moisture, and
ascent attendant to a low-amplitude shortwave trough progressing
through the region will support scattered to numerous thunderstorms
from eastern NV across UT into northwest CO/southern WY. Some
isolated hail is possible with the strongest cores (which could
briefly acquire supercellular characteristics), but the primary
severe risk is strong to severe wind gusts. Highest severe coverage
is still expected from east-central NV into northern UT where the
greatest afternoon buoyancy is forecast.

...Northeast CO/eastern WY/NE Panhandle into the western/central
Dakotas...
High-based showers and thunderstorms along the leading edge of the
strongest ascent attendant to the shortwave trough moving through
the Great Basin and central Rockies should emerge into a diurnally
destabilized and moderately buoyant airmass from northeast CO into
eastern WY and the NE Panhandle during the late afternoon/early
evening. This could result in reintensification, and a risk for both
large hail and damaging gusts across the region throughout the
evening. Most of the guidance was overly aggressive with
destabilization and buoyancy across this region yesterday, and there
is some concern that cloud cover could again limit heating. That
being said, there is a pocket of greater low-level moisture across
SD and the region is currently under widely scattered cloud cover.
Enhanced westerly flow atop low-level easterlies will support at
least moderate deep-layer shear, so any updrafts that can mature
should be able to organize, with an attendant risk for large hail
and damaging gusts.

...AZ...
12Z PHX sounding sampled moderate mid-level moisture atop warm and
dry low levels. Scattered thunderstorm development is anticipated
across much of the region. Vertical shear is weak and a largely
disorganized storm mode is anticipated. Still, given the high storm
bases and steep low-level lapse rates, isolated strong to severe
gusts are possible this afternoon and evening.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 30 00:58:22 2026

ACUS01 KWNS 300058
SWODY1
SPC AC 300056

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 PM CDT Sat Aug 29 2026

Valid 300100Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE GREAT
BASIN AND CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Widely scattered strong to severe storms are expected across parts
of the northern Great Basin, northern/central Rockies, and
northern/central Plains. Isolated severe wind gusts are the main
threat, though some hail is also possible.

...Great Basin and Rockies...
An upper low, and several weak perturbations embedded within a belt
of enhanced mid-level flow with moving across the Great Basin are
supporting scattered thunderstorms across the eastern Great Basin
and Intermountain West this evening. Plentiful monsoon moisture
remains in place contributing to modest buoyancy. This will support
scattered to numerous storms through much of the evening and
overnight. 50-55 kt of mid-level flow, and relatively dry sub cloud
layers will continue to support strong downdrafts with the potential
for severe wind gusts and isolated hail. This appears most likely
across eastern NV and northern UT where the air mass remains the
most unstable. However, sporadic damaging gusts are possible across
much of the Rockies and Four Corners where storms are forecast to
remain active tonight.

...Central Plains...
High-based convection across eastern CO/WY and western NE has
gradually weakened as it has encountered a much drier and more
stable air mass across the High Plains. Isolated strong to severe
gusts will remain possible with this activity, and other
showers/storms emanating from the terrain this evening.

More isolated storms, including supercells, across eastern SD are
expected to continue this evening with isolated hail and severe wind
potential. As the lead shortwave trough continues eastward this
evening, increasing low-level warm advection could support
additional elevated storm development from eastern SD to
south-central ND. Moderate buoyancy atop the stable surface layer
amid 40-50 kts of effective shear would support supercells with
isolated hail possible through the overnight hours.

...AZ...
Scattered thunderstorms ongoing across southern AZ should slowly
drift northwest through this evening within a very hot and
moderately unstable air mass. Vertical shear is weak and a largely
disorganized storm mode is likely. Still, steep low-level lapse
rates will favor strong downdrafts with isolated severe gusts
possible.

..Lyons.. 08/30/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 30 05:55:24 2026

ACUS01 KWNS 300555
SWODY1
SPC AC 300553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Sun Aug 30 2026

Valid 301200Z - 311200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
NORTHERN PLAINS...PARTS OF THE CENTRAL HIGH PLAINS AND THE EASTERN
GREAT BASIN...

...SUMMARY...
Isolated severe storms, accompanied by mainly a severe wind and hail
threat, are possible across portions of the northern and central
Plains, as well as the eastern Great Basin today and tonight.

...Northern Plains...
An upper low over SK is forecast to eject eastward as it is
entrained in the stronger westerlies associated with a low-amplitude
shortwave trough crossing the northern Rockies. A belt of enhanced
mid-level flow will extend westward over the Intermountain West and
northern Great Basin, coincident with a plume of mid-level monsoon
moisture. A surface low will develop during the afternoon from near
the MT/ND border with a trailing cold front forecast to move across
the Dakotas overnight. A weaker low/surface trough will develop
across the central High Plains as a warm front extends eastward from
SD into southern MN, WI and Lower MI.

Morning storms along the warm front from the eastern Dakotas to
western MN could persist and pose a risk for isolated hail. The
primary low-level jet will remain displaced to the south which
should allow these storms to weaken through the remainder of the
day.

More robust convection is expected to develop ahead of the cold
front from eastern MT/WY into the western and central Dakotas. Weak
low-level easterly flow will help transport mid 60s dewpoints
westward aiding in moderate destabilization. Flow aloft will
increase through the day, though the strongest deep-layer shear
should lag behind the front. Nevertheless, a band of storms, likely
a mix of line segments and some supercell structures, should develop
and intensify along the cold front spreading eastward. Some severe
gusts, hail above 1.00" and perhaps a tornado near the warm front
are possible. The severe risk may persist through the night as
activity pushes across ND/SD and into MN.

..Front Range to the High Plains...
As the trough moves overhead through the day, high based convection
is forecast to develop and move off the higher terrain of CO/WY,
aided by 30-40 kt mid-level westerlies. Steep low-level lapse rates
and high cloud bases may support localized damaging wind potential
across CO/NE/KS. Some organization into a cluster is possible as the
storms move eastward into the Plains through the evening. However,
modest buoyancy may inhibit broader intensification/organization.

...Great Basin/Western Slope...
An unseasonably moist air mass (dewpoints in the 50s to near 60 F)
will be in place beneath the stronger mid-level flow from eastern UT
into western CO. Showers and storms are likely to be ongoing at the
start of the period and should increase in coverage trough the day
aided by filtered diurnal heating and the passage of the shortwave
trough crossing the Rockies. While destabilization will be
contingent on cloud breaks, pockets of moderate buoyancy amid the
strong unidirectional westerly flow may support a few organized
storm clusters or supercells capable of isolated severe gusts and
hail.

...AZ/CA...
Scattered thunderstorms are again expected to develop within a hot
and moderately unstable air mass this afternoon. Stronger mid-level
flow should be well to the north supporting little if any storm
organization. Still, steep low-level lapse rates could support
sporadic downbursts with occasional severe gusts. Severe coverage is
expected to remain below 5%.

..Lyons/Wendt.. 08/30/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 30 12:16:24 2026

ACUS01 KWNS 301216
SWODY1
SPC AC 301214

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0714 AM CDT Sun Aug 30 2026

Valid 301300Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PARTS OF THE DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...MT/ND/SD...
Morning water vapor loop shows a strong upper trough over ID
tracking east-northeastward. This system will emerge onto the
Plains of eastern MT/western Dakotas by late afternoon today, when
strong heating will result in a corridor of surface temperatures
near 90F along the MT/ND border ahead of an approaching cold front. Thunderstorms will intensify in vicinity of this front through the
afternoon, tracking quickly eastward into parts of western/central
ND/SD by 00z. Morning CAM solutions suggest storms will organize
into a line with the risk of severe wind gusts. Given the strength
of the low and mid-level flow near the front, that scenario seems
plausible. Therefore have added a SLGT risk to parts of this
region.

...CO/KS/NE...
South of the primary severe threat, a secondary area of concern will
develop this afternoon as storms develop over the mountains of
central CO and spread eastward into the Plains. This activity will
be high-based and in a weakly unstable environment. Nevertheless,
strong outflow winds will be possible with the activity, spreading
eastward into western NE and northwest KS during the evening.

...UT/Western CO...
Considerable low-level moisture will remain over UT today, leading
to another round of strong thunderstorms this afternoon. Deep-layer
shear remains sufficient for rotating storms capable of damaging
wind gusts and hail. Activity should spread into western CO by
early evening before weakening.

..Hart/Broyles.. 08/30/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 30 16:31:24 2026

ACUS01 KWNS 301631
SWODY1
SPC AC 301629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sun Aug 30 2026

Valid 301630Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST MONTANA AND FAR NORTHEAST WYOMING INTO THE
CENTRAL DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...Northern High Plains into the northern Plains...
Recent satellite imagery shows a well-defined shortwave trough
moving eastward across southern Saskatchewan and western MT/eastern
ID. A belt of stronger westerly flow aloft likely exists within the
base of this trough from eastern ID into western WY. Recent
mesoanalysis estimates 50 to 60 kt at 500 mb, but its actual
magnitude is uncertain. Showers and isolated thunderstorms are
already ongoing downstream of this wave, and the general expectation
is for these showers and thunderstorms to persist as the wave moves
eastward, eventually encountering a notably more unstable airmass
downstream.

Current surface observations show mid 60s dewpoints into the western
Dakotas, with upper 50s/low 60s dewpoints farther west in eastern
MT. Afternoon high temperatures are expected range from the low to
mid 80s along the MT/ND border into the low 90s farther south into
southwest SD. Despite relatively poor pre-frontal mid-level lapse
rates, the resulting temperature/dewpoint combination will support
MLCAPE ranging from around 500-1000 J/kg across eastern MT and the
western Dakotas to closer to 2000 J/kg across the central Dakotas.
Some low-level stability may linger, but should be overcome by the
strong forcing, and the development of a line of strong to severe
storms is anticipated. Strong to severe gusts will be the primary
risk, with some instance of gusts from 65 to 80 mph possible.
Maximum storm intensity and highest severe coverage is currently
forecast to occur from the ND/SD/MT border intersection vicinity
eastward into south-central ND and north-central SD. Decreasing
buoyancy is expected from the central Dakotas eastward, with
gradually decreasing storm intensity expected as the line of storms
moves into this region this evening.

...Central High Plains...
Increased coverage and depth of the thunderstorms across UT indicate
the presence of secondary area of ascent south of the primary
shortwave trough, perhaps tied to a convectively augmented vorticity
maximum. Expectation is for this vorticity maximum to progress
eastward, persisting across the central Rockies before entering
deeply mixed boundary-layer in place over the central High Plains.
High-based storm character coupled with steep low-level lapse rates
will support the development of strong outflow, and gusts from 60 to
75 mph are possible.

...UT/Western CO...
Thunderstorms are already ongoing from eastern UT into western CO,
and deep-layer vertical shear is already strong enough to support
organization within any more persistent updrafts. A few instances of
hail and/or damaging gusts are possible with this activity.
Additionally, considerable low-level moisture will remain over UT
today, leading to another round of strong to isolated severe
thunderstorms this afternoon. Deep-layer shear will remain
sufficient for rotating storms capable of damaging wind gusts and
hail. This additional activity should also spread into western CO
before weakening this evening.

...Central/Southern AZ...
Ample low-level moisture remains in place across much of AZ, with
upper 50s dewpoints across northern AZ increasing into the mid 60s
across southern AZ. Another day of afternoon thunderstorms is
anticipated as this moist airmass destabilizes amid strong diurnal
heating. High-based storms coupled with moderate buoyancy and steep
low-level lapse rates could result in a few strong to severe gusts
across the region this afternoon and evening.

..Mosier/Moore.. 08/30/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 30 19:47:56 2026

ACUS01 KWNS 301947
SWODY1
SPC AC 301946

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Sun Aug 30 2026

Valid 302000Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST MONTANA AND FAR NORTHEAST WYOMING INTO THE
CENTRAL DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...20z Update...
Only minor changes were made to remove the Marginal Risk from behind
ongoing convection in eastern Montana. Otherwise, the D1 Convective
Outlook remains on track. See previous discussion and MCD #2174 for
more information.

..Thornton.. 08/30/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Sun Aug 30 2026/

...Northern High Plains into the northern Plains...
Recent satellite imagery shows a well-defined shortwave trough
moving eastward across southern Saskatchewan and western MT/eastern
ID. A belt of stronger westerly flow aloft likely exists within the
base of this trough from eastern ID into western WY. Recent
mesoanalysis estimates 50 to 60 kt at 500 mb, but its actual
magnitude is uncertain. Showers and isolated thunderstorms are
already ongoing downstream of this wave, and the general expectation
is for these showers and thunderstorms to persist as the wave moves
eastward, eventually encountering a notably more unstable airmass
downstream.

Current surface observations show mid 60s dewpoints into the western
Dakotas, with upper 50s/low 60s dewpoints farther west in eastern
MT. Afternoon high temperatures are expected range from the low to
mid 80s along the MT/ND border into the low 90s farther south into
southwest SD. Despite relatively poor pre-frontal mid-level lapse
rates, the resulting temperature/dewpoint combination will support
MLCAPE ranging from around 500-1000 J/kg across eastern MT and the
western Dakotas to closer to 2000 J/kg across the central Dakotas.
Some low-level stability may linger, but should be overcome by the
strong forcing, and the development of a line of strong to severe
storms is anticipated. Strong to severe gusts will be the primary
risk, with some instance of gusts from 65 to 80 mph possible.
Maximum storm intensity and highest severe coverage is currently
forecast to occur from the ND/SD/MT border intersection vicinity
eastward into south-central ND and north-central SD. Decreasing
buoyancy is expected from the central Dakotas eastward, with
gradually decreasing storm intensity expected as the line of storms
moves into this region this evening.

...Central High Plains...
Increased coverage and depth of the thunderstorms across UT indicate
the presence of secondary area of ascent south of the primary
shortwave trough, perhaps tied to a convectively augmented vorticity
maximum. Expectation is for this vorticity maximum to progress
eastward, persisting across the central Rockies before entering
deeply mixed boundary-layer in place over the central High Plains.
High-based storm character coupled with steep low-level lapse rates
will support the development of strong outflow, and gusts from 60 to
75 mph are possible.

...UT/Western CO...
Thunderstorms are already ongoing from eastern UT into western CO,
and deep-layer vertical shear is already strong enough to support
organization within any more persistent updrafts. A few instances of
hail and/or damaging gusts are possible with this activity.
Additionally, considerable low-level moisture will remain over UT
today, leading to another round of strong to isolated severe
thunderstorms this afternoon. Deep-layer shear will remain
sufficient for rotating storms capable of damaging wind gusts and
hail. This additional activity should also spread into western CO
before weakening this evening.

...Central/Southern AZ...
Ample low-level moisture remains in place across much of AZ, with
upper 50s dewpoints across northern AZ increasing into the mid 60s
across southern AZ. Another day of afternoon thunderstorms is
anticipated as this moist airmass destabilizes amid strong diurnal
heating. High-based storms coupled with moderate buoyancy and steep
low-level lapse rates could result in a few strong to severe gusts
across the region this afternoon and evening.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 31 00:59:26 2026

ACUS01 KWNS 310059
SWODY1
SPC AC 310057

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Sun Aug 30 2026

Valid 310100Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Severe storms capable of damaging wind gusts remain likely across
portions of the northern Plains this evening.

...Northern Plains...
Evening water-vapor imagery showed a strong, negative-tilt mid-level
low and embedded shortwave trough ejecting eastward across southern
SK into eastern MT. Accompanying the low, a prominent mid-level jet
streak (60-70 kt) was quickly moving across the Rockies and into the
Plains. A cold front, attendant to a surface low in southern Canada,
will sweep quickly eastward across the Dakotas tonight.

A well-develop squall line was observed along/ahead of the front
from southern SK/MB to northern SD this evening. Within the line,
numerous strong to severe gusts have been observed thus far. Aided
by the enhanced mid-level flow ahead of the advancing upper trough,
ascent will continue to support the line as it moves eastward this
evening. The air mass downstream in the eastern Dakotas has remained
sheltered much of the day, but is very moist with dewpoints in the
upper 60s to low 70s F. Given the presence of an established cold
pool and sufficient deep-layer shear, especially along the southern
portions of the squall line, the severe threat may continue eastward
this evening across southern ND and SD into the late evening hours,
with a risk for damaging gusts.

Eventually, increasing nocturnal inhibition and the weaker buoyancy
should favor a decreasing severe risk. Convection may transition to
more elevated structures above the more stable PBL with an isolated
risk for occasional damaging gusts and some hail into the overnight
hours across eastern ND and western MN.

...Central Rockies and High Plains...
At the base of the upper low and shortwave, scattered thunderstorms
were ongoing from eastern UT into western/central CO this evening.
Enhanced mid-level flow is supporting organized clusters and some
rotating storms. Hail or severe gusts are possible. Convection
should weaken as it enters the more stable and cooler higher terrain
across central CO. Sporadic strong gusts or small hail remain
possible withe more robust storms in the mountains through tonight.

East of the Divide, high-based showers and thunderstorms should
increase in coverage this evening as a secondary mid-level vorticity
maximum moves out over the Plains. Increasing ascent amid warm
surface temperatures and steep low-level lapse rates (00z DDC
sounding) should support strong downdrafts capable of severe gusts
in the 60-75 mph range. 30-40 kt of deep-layer shear will support
some conglomeration with hi-res model guidance showing a cluster or
weak MCS moving across the High Plains of eastern CO, and western
KS/NE this evening/tonight.

...AZ...
Scattered thunderstorms over the lower deserts should persist
through this evening given very hot surface temperatures and
seasonable monsoon moisture. Moderate buoyancy but weak deep-layer
shear should support multicell storms. Steep low-level lapse rates
could result in a few strong to severe gusts this evening.

..Lyons.. 08/31/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 31 06:03:48 2026

ACUS01 KWNS 310603
SWODY1
SPC AC 310601

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Mon Aug 31 2026

Valid 311200Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL HIGH PLAINS TO GREAT LAKES AND LOWER COLORADO RIVER
VALLEY/GREAT BASIN...

...SUMMARY...
Isolated severe storms will be possible mainly later this afternoon
into tonight across the Upper Midwest/upper Great Lakes into the
central Plains, as well as across the lower Colorado River Valley
and Great Basin.

...Eastern Colorado/central High Plains to Upper Great Lakes...
A prominent shortwave trough will spread east-northeastward across
Saskatchewan and Manitoba through tonight, with 40-50 kt mid-level
winds spreading across the Northern Plains and Upper Mississippi
Valley. Across the Upper Midwest, a moist air mass will persist near
a weak surface trough, with 2000-3000 J/kg MUCAPE from Iowa into
Wisconsin and northern Illinois. However, forcing for ascent will
generally be weak, but isolated afternoon thunderstorms may occur
over areas such as Wisconsin. Conditionally, hail over 1.00" will be
possible. Additional isolated activity is possible from Iowa into
northern Illinois/northern Michigan late tonight.

A greater probability of thunderstorms will exist across eastern
Colorado into Nebraska from mid/late afternoon into tonight,
influenced by a northeastward-advancing mid-level wave. Strong
heating over the central High Plains will support afternoon
initiation near the Front Range, with clusters of storms producing
strong to severe outflow winds, as storms potentially propagate into
Nebraska. Bouts of severe hail and winds are possible.

...Lower Colorado River Valley/Great Basin...
A northeastward-transitioning mid-level disturbance or two will
influence thunderstorm development as the boundary layer warms into
this afternoon. Some enhancement to the flow aloft is expected,
which could support some sustained storms and possibly a few
transient supercells, primarily across far eastern Nevada, southwest
Utah and northwest Arizona. Some hail could occur, but
severe-caliber wind gusts are most probable hazard regionally.

...Southern Louisiana/Gulf Coast...
Reference NHC for the latest details regarding a disturbance off the
coast of southern Louisiana. Related low-level flow fields are
currently not expected to strengthen enough to support a meaningful near-shore/inland supercell potential through early Tuesday.

..Guyer/Wendt.. 08/31/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 31 18:02:46 2026

ACUS01 KWNS 311628
SWODY1
SPC AC 311626

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1126 AM CDT Mon Aug 31 2026

Valid 311630Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST/GREAT LAKES INTO WESTERN NEW YORK...THE CENTRAL
PLAINS...AND LOWER COLORADO RIVER VALLEY INTO THE GREAT BASIN...

...SUMMARY...
Isolated strong to severe thunderstorms may occur this afternoon
into tonight across parts of the Upper Midwest/Great Lakes into
western New York, the central Plains, and lower Colorado River
Valley into the Great Basin. Severe hail and strong/damaging winds
should be the main threats.

...Upper Midwest/Great Lakes into Western New York...
A closed mid/upper-level low over the northern Plains and
Saskatchewan/Manitoba will move generally eastward today, with a
mid-level anticyclone remaining centered over the mid MS
Valley/Mid-South through the period. Between these two features, a
belt of enhanced westerly mid-level winds will overspread parts of
the Upper Midwest and Great Lakes. A rather moist and strongly
unstable airmass is expected to be in place this afternoon across
portions of WI/MI ahead of a weak front. While there are still some
concerns about convective initiation and overall thunderstorm
coverage, it appears that a weak mid-level perturbation over eastern
NE/western IA late this morning will track northeastward towards WI
by late afternoon/early evening. This feature may aid the
development of isolated to widely scattered thunderstorms across
parts of WI into the U.P. of MI.

Given strong to very strong instability and moderate to strong
deep-layer shear forecast, widely spaced supercells capable of
producing large hail appear possible late this afternoon into the
evening across these areas, if convection develops. Considered
greater hail probabilities to account for this scenario, but warm
low-level temperatures (around 850 mb) and mixed signals in
high-resolution guidance cast enough uncertainty on coverage to
defer upgrading with this update. Thunderstorms may also spread from
Lower MI into western NY tonight into early Tuesday morning.
Increasing low-level moisture and related instability may support an
isolated threat for damaging winds with this activity, even though
lapse rates aloft should remain modest.

...Central Plains...
High-based thunderstorms should develop this afternoon across the
higher terrain of the central Rockies/Front Range, and spread east-northeastward across the adjacent High Plains through the
evening. While low-level moisture/instability will remain limited
across eastern CO and vicinity, steepened low/mid-level lapse rates
amid a very well-mixed boundary layer may still support isolated
strong to severe downdraft winds with this activity. Occasional hail
may also occur with the strongest cores. Thunderstorm coverage
farther east across NE along/near a weak front remains uncertain.
But, any convection which can develop and be sustained across this
area may also pose an isolated severe threat.

...Lower Colorado River Valley into the Great Basin...
A mid-level shortwave trough over CA will move northeastward across
NV today and aid thunderstorm development as the boundary layer
warms into this afternoon across parts of the lower CO River Valley
and Great Basin. Some enhancement to the mid-level flow is forecast,
which should support sustained updrafts and possibly a few transient supercells, primarily across far eastern NV, southwest UT, and
northwest AZ. Isolated severe hail could occur with these cells.
But, strong to severe wind gusts will probably become the primary
risk with time given steep low-level lapse rates and tendency for
convection to cluster through the late afternoon/early evening.

...Coastal/Southeast Texas into Southern Louisiana...
Reference NHC forecasts/advisories for the latest information on PTC
Five over the northern Gulf. Latest model guidance continues to
suggest that low-level easterly flow on the northern side of this
system will only modestly strengthen before landfall tomorrow. As
such, the degree of low-level shear appears too limited to warrant
low severe wind or tornado probabilities at this time.

..Gleason/Moore.. 08/31/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 31 19:31:10 2026

ACUS01 KWNS 311929
SWODY1
SPC AC 311928

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0228 PM CDT Mon Aug 31 2026

Valid 312000Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST/GREAT LAKES INTO WESTERN NEW YORK...THE CENTRAL
PLAINS...AND LOWER COLORADO RIVER VALLEY INTO THE GREAT BASIN...

...SUMMARY...
Isolated strong to severe thunderstorms may occur this afternoon
into tonight across parts of the Upper Midwest/Great Lakes into
western New York, the central Plains, and lower Colorado River
Valley into the Great Basin. Severe hail and strong/damaging winds
should be the main threats.

...20z Update...
Minor adjustments were made to remove the Marginal Risk across
portions of northern Arizona/far southern Nevada where lingering precipitation/cloud cover is limiting instability and drier
mid-level air is filtering in from the west. Otherwise, the forecast
remains on track. See previous discussion below for more
information.

..Thornton.. 08/31/2026

.PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Aug 31 2026/

...Upper Midwest/Great Lakes into Western New York...
A closed mid/upper-level low over the northern Plains and
Saskatchewan/Manitoba will move generally eastward today, with a
mid-level anticyclone remaining centered over the mid MS
Valley/Mid-South through the period. Between these two features, a
belt of enhanced westerly mid-level winds will overspread parts of
the Upper Midwest and Great Lakes. A rather moist and strongly
unstable airmass is expected to be in place this afternoon across
portions of WI/MI ahead of a weak front. While there are still some
concerns about convective initiation and overall thunderstorm
coverage, it appears that a weak mid-level perturbation over eastern
NE/western IA late this morning will track northeastward towards WI
by late afternoon/early evening. This feature may aid the
development of isolated to widely scattered thunderstorms across
parts of WI into the U.P. of MI.

Given strong to very strong instability and moderate to strong
deep-layer shear forecast, widely spaced supercells capable of
producing large hail appear possible late this afternoon into the
evening across these areas, if convection develops. Considered
greater hail probabilities to account for this scenario, but warm
low-level temperatures (around 850 mb) and mixed signals in
high-resolution guidance cast enough uncertainty on coverage to
defer upgrading with this update. Thunderstorms may also spread from
Lower MI into western NY tonight into early Tuesday morning.
Increasing low-level moisture and related instability may support an
isolated threat for damaging winds with this activity, even though
lapse rates aloft should remain modest.

...Central Plains...
High-based thunderstorms should develop this afternoon across the
higher terrain of the central Rockies/Front Range, and spread east-northeastward across the adjacent High Plains through the
evening. While low-level moisture/instability will remain limited
across eastern CO and vicinity, steepened low/mid-level lapse rates
amid a very well-mixed boundary layer may still support isolated
strong to severe downdraft winds with this activity. Occasional hail
may also occur with the strongest cores. Thunderstorm coverage
farther east across NE along/near a weak front remains uncertain.
But, any convection which can develop and be sustained across this
area may also pose an isolated severe threat.

...Lower Colorado River Valley into the Great Basin...
A mid-level shortwave trough over CA will move northeastward across
NV today and aid thunderstorm development as the boundary layer
warms into this afternoon across parts of the lower CO River Valley
and Great Basin. Some enhancement to the mid-level flow is forecast,
which should support sustained updrafts and possibly a few transient supercells, primarily across far eastern NV, southwest UT, and
northwest AZ. Isolated severe hail could occur with these cells.
But, strong to severe wind gusts will probably become the primary
risk with time given steep low-level lapse rates and tendency for
convection to cluster through the late afternoon/early evening.

...Coastal/Southeast Texas into Southern Louisiana...
Reference NHC forecasts/advisories for the latest information on PTC
Five over the northern Gulf. Latest model guidance continues to
suggest that low-level easterly flow on the northern side of this
system will only modestly strengthen before landfall tomorrow. As
such, the degree of low-level shear appears too limited to warrant
low severe wind or tornado probabilities at this time.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 1 00:54:38 2026

ACUS01 KWNS 010054
SWODY1
SPC AC 010052

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 PM CDT Mon Aug 31 2026

Valid 010100Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE GREAT BASIN...THE CENTRAL PLAINS...AND THE MIDWEST/GREAT
LAKES...

...SUMMARY...
Isolated strong to severe thunderstorms remain possible into tonight
across parts of the Upper Midwest/Great Lakes into western New York,
the central Plains, and lower Colorado River Valley into the Great
Basin. Severe hail and strong/damaging winds should be the main
threats.

...Great Lakes to western NY...
Evening water-vapor imagery showed an occluded upper low over MB/AB
moving eastward with a low-amplitude shortwave trough over the
central Plains. A corridor of enhanced mid-level westerly flow was overspreading the Midwest and western Great Lakes. At the surface, a
weak cold front was moving from southern Canada into western WI and
trailing westward across the central Plains.

A rather moist and strongly unstable air mass remains in place this
evening across portions of WI/MI ahead of the surface front. So far,
weak forcing for ascent and residual inhibition has prevent much in
the way of robust convection. Isolated development will remain
possible, as hinted by short term guidance, through later this
evening given the strong instability and glancing influence of the
upper low/trough. While uncertain, if storms are able to develop,
45-50 kt of bulk shear would support supercells with damaging wind
and some hail potential across eastern WI into lower MI.

Thunderstorms may also spread from Lower MI and southern ON into
western NY tonight into early Tuesday morning aided by low-level
warm air advection. Increasing instability may support an isolated
threat for damaging winds overnight.

...Central Plains...
High-based thunderstorms ongoing across the High Plains of CO will
continue to track northeastward along the surface front this
evening. Hot surface temperatures have helped steepen low/mid-level
lapse rates and will support isolated strong to severe downdraft
winds with this activity. Occasional hail may also occur with the
strongest cores thanks to some organization from a belt of stronger
mid-level flow. This organization and coalescing outflow could
support some clustering later tonight. See MCD#2138 for additional
information.

...Great Basin...
Scattered thunderstorms are ongoing this evening over portions of
southern UT/NV. Aided by strong heating of a monsoon air mass and
weak ascent from a passing shortwave trough, these storms should
continue into the overnight hours. Modestly enhanced mid-level flow
and steep low-level lapse rates will support severe wind potential
and some risk for hail with the stronger clusters or transient
supercells. Much weaker buoyancy to the north may limit severity of
the convection as they encounter the more stable air mass this
evening.

...Coastal/Southeast Texas into Southern Louisiana...
Reference NHC forecasts/advisories for the latest information on TD
5. Low-level easterly flow on the northern side of the TC
should remain modest ahead of a forecast landfall tomorrow. This,
combined with the compact nature of the system favors weak low-level
shear and limited potential for onshore bands with tornado or
thunderstorm driven damaging wind potential.

..Lyons.. 09/01/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 1 06:04:40 2026

ACUS01 KWNS 010604
SWODY1
SPC AC 010603

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0103 AM CDT Tue Sep 01 2026

Valid 011200Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL/NORTHERN PLAINS AND MIDWEST INTO PARTS OF PENNSYLVANIA
NEW YORK AND NEW JERSEY....

...SUMMARY...
Scattered strong to severe storms are possible over the central
Plains and Midwest, as well as parts of New York, Pennsylvania and
New Jersey.

...Eastern Great Lakes, OH valley and NY/NJ...
Scattered showers and thunderstorms are expected to be ongoing early
in the period across parts of NY associated with a lead shortwave
trough and warm advection. Remnant clouds, showers and storms should
persist trough the day along a northwest to southeast warm front
across northern/eastern NY into NJ. A second shortwave trough and
mid-level jet will approach during the afternoon providing ascent
across the upper OH Valley and NY.

Despite modest mid-level lapse rates, 70s F surface dewpoints and
strong heating will support a very unstable air mass with MLCAPE of
3000+ J/kg south of the warm front. Increasing vertical shear ahead
of the mid-level speed max will favor a mix of supercells and line
segments across southern NY, PA and NJ through the afternoon.
Scattered damaging gusts and isolated hail are the most likely
hazards. Low-level shear will be greatest near the southern Hudson
Valley and the instability gradient into northeast PA/northern NJ.
Enhanced ESRH could support a couple of tornadoes with the stronger
supercells or QLCS segments.

Some guidance shows additional thunderstorms developing over
southern lower MI and ON early Wed, associated with another
mid-level wave speed max across the eastern Great Lakes. Sufficient
elevated buoyancy (2000 J/kg MUCAPE) and vertical shear will exist
for some damaging wind threat should this occur. This scenario
remains uncertain, but these storms could potentially track
southeast and organize, approaching northeast OH and western NY/PA
by 12z Wed morning.

...Central/northern Plains...
A stalled front will lift northward across parts of NE/SD as several low-amplitude shortwave troughs move out of the Rockies and onto the
Plains. Weak ascent from these features will modestly deepen a
surface low across NE and SD. In response, strengthening southerly flow/moisture should result in moderate to strong destabilization by
early afternoon.

Convection lingering from overnight may begin to rejuvenate along
and north of the front across SD as heating increases through the
afternoon. Meanwhile, inhibition owing to warm mid-level
temperatures will likely remain in place most of the day south of
the front. Weak ascent and strong heating should be sufficient to
support isolated storm development by late afternoon. A belt of
enhanced southwesterly flow aloft would favor organization with
supercell or strong clusters likely. Hail (some 2+ inch) is possible
along with damaging gusts given a supercell mode. A tornado or two
is also possible given the potential for supercells to reside along
the boundary where low-level flow will be substantially backed and
hodographs expanded.

Eventually, one or more clusters may merge into an MCS and track
eastward along the front into eastern SD and southern MN through the
evening. Damaging gusts will be possible if this convection can
organize through the late evening/overnight hours. Model guidance
varies on the intensity and organization of the system. However,
confidence has increased enough that 15% CIG1 wind probabilities
have been added along the front.

...High Plains...
To the southwest along the surface lee trough, high-based convection
is likely to develop around peak heating across southwestern NE into
eastern Co and western KS. Despite more limited surface moisture,
very warm temperatures and steep lapse rates in the lower/middle
troposphere will promote strong multicell clusters. These storms
could produce severe gusts as they move east/northwest eventually
moving into more unstable air.

...Upper TX Coast...
TS Eduardo located near 28.6N 91.8W as of 10 pm CDT is forecast to
move toward the southwest LA/southeast TX coast and make landfall
tonight. Wind fields are forecast to remain relatively confined
given its small size and fast westward motion. This should limit
stronger low-level shear favorable for supercells and tornadoes.

..Lyons/Wendt.. 09/01/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 1 12:13:42 2026

ACUS01 KWNS 011213
SWODY1
SPC AC 011212

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0712 AM CDT Tue Sep 01 2026

Valid 011300Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
OVER PARTS OF THE NORTHEAST STATES...AND THIS EVENING OVER THE
CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST....

...SUMMARY...
Scattered strong to severe storms are possible over the central
Plains and Midwest, as well as parts of New York, Pennsylvania and
New Jersey.

...Northeast...
A broad upper ridge remains in place over the Mid MS/TN Valleys,
with northwest flow aloft affecting the northeast US and
Mid-Atlantic states. The main baroclinic zone in this region
currently extends from central NY into southern New England, with
dewpoints in the mid-upper 60s along and south of the boundary. This
air mass is expected to destabilize through the day as temperatures
warm through the 80s, leading to a zone of strong instability
(MLCAPE of 2500+ J/kg) over parts of PA/NY/NJ. Ongoing convection
may delay daytime heating, but eventually strong storms are expected
to form in this region, spreading southeastward through the late
afternoon and evening. Damaging winds are the primary concern,
although some hail and a tornado or two cannot be ruled out. A lack
of a more obvious upper feature to aid in large-scale forcing may
limit the overall coverage of severe storms.

...SD/NE/MN/IA...
A shortwave trough currently over western CO will track quickly
northeastward and affect the central Plains by late afternoon.
Strong heating and a moist air mass will yield moderate CAPE over
parts of SD/NE. Low-level warm advection and diurnal heating will
lead to scattered thunderstorm development over central SD by late
afternoon. Initial supercell storms are expected, capable of
damaging winds, large hail, and perhaps a tornado. Storms are
expected to become more numerous during the evening and grow upscale
into bowing structures, with a damaging wind risk tracking eastward
into parts of southern MN and perhaps northern IA. Some guidance
suggests storms will maintain some damaging wind risk into central
WI overnight.

...Southwest LA/Southeast TX...
Tropical Storm Eduardo is expected to strengthen today off the
immediate LA/TX coast and move inland this afternoon and evening.
Models continue to show limited discrete convection in the northeast
quadrant of the system, suggested a rather low tornado risk today. Nevertheless, given the potential for rapid strengthening around the
time of landfall, have opted for a small 2% tornado risk area for a
few hours this evening.

..Hart/Dean.. 09/01/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 1 16:30:54 2026

ACUS01 KWNS 011630
SWODY1
SPC AC 011628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Tue Sep 01 2026

Valid 011630Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN NEW YORK INTO THE MID-ATLANTIC...AND THE NORTHERN/CENTRAL
PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Scattered strong to severe thunderstorms should occur this afternoon
into tonight across parts of the northern/central Plains and Upper
Midwest, and parts of southern New York into the Mid-Atlantic. Large
hail and damaging winds should be the main threats.

...Mid-Atlantic/Southern New York...
A mid/upper-level anticyclone will remain centered over the TN
Valley/Mid-South today, with a mid-level shortwave trough forecast
to move eastward across Ontario through the period. In between these
features, a belt of enhanced west-northwesterly flow will exist
across the Great Lakes into the Mid-Atlantic. Latest surface
observations show a front draped from northwest to southeast across
southern NY/New England, with cloud cover and precipitation ongoing
across these areas. Current expectations are for destabilization to
occur along/south of the front through the afternoon, with modestly
steepened mid-level lapse rates present across MI (reference 12Z
observed APX/DTX soundings) forecast to advect southeastward across
the Mid-Atlantic. Moderate to strong instability will likely develop
by mid afternoon across PA/NJ, with 30-40 kt of deep-layer shear
fostering updraft organization.

While there is still some uncertainty regarding overall convective
development and evolution this afternoon/evening owing to nebulous
large-scale ascent, most high-resolution guidance develops isolated
to widely scattered thunderstorms along/south of the front,
particularly over eastern PA into NJ and vicinity. Supercells with a
severe hail/wind threat will be possible initially, and enough
low-level shear may exist near the front for a tornado or two as
well. Whether convection can grow upscale into one or more clusters
also remains uncertain. But if this occurs, then the threat for
damaging winds may increase late this afternoon into the evening
given the rather favorable environment forecast.

...Northern/Central Plains into the Upper Midwest/Great Lakes...
A mid-level shortwave trough over the northern/central Rockies and
adjacent High Plains this morning will translate northeastward today
over the northern/central Plains. A moist and unstable airmass will
reside along/south of a front forecast to extend generally west to
east across parts of southern SD/northern NE into southern
MN/northern IA. Robust thunderstorm development appears increasingly
likely by 21-23Z across north-central NE as large-scale ascent
preceding the shortwave trough overspreads the destabilizing warm
sector. Latest NAM/RAP forecast soundings across this region show up
to 1500-2500 J/kg of MLCAPE and strong deep-layer shear, which will
likely support supercells initially. With steepened low/mid-level
lapse rates and elongated/nearly straight hodographs at mid levels
depicted, some potential for 2+ inch hail may exist with these
supercells. A tornado or two also appears possible as low-level
shear gradually increases after 02/00Z. With time, a bowing cluster
is expected to develop across eastern SD/northeast NE this evening,
and subsequently track eastward across southern MN/northern IA with
a severe/damaging wind threat overnight. Some risk for damaging
winds and hail may continue into early Wednesday morning across
parts of WI and Lower MI as well.

...Coastal Southeast Texas/Southwest Louisiana...
Tropical Storm Edouard will continue tracking northwestward today,
per latest NHC forecasts. Some enhancement to the low-level wind
field and hodograph is noted on the latest VWP and 15Z special
observed sounding from KLCH. This may support transient updraft
rotation with any cells on the north to northeast side of Edouard's circulation, and a brief tornado or two may occur this
afternoon/evening across parts of coastal southeast TX/southwest LA
as filtered diurnal heating supports modest destabilization.

..Gleason/Moore.. 09/01/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 1 20:02:44 2026

ACUS01 KWNS 012002
SWODY1
SPC AC 012000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Tue Sep 01 2026

Valid 012000Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN NEW YORK INTO THE MID-ATLANTIC...AND THE NORTHERN/CENTRAL
PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Scattered strong to severe thunderstorms should occur this afternoon
into tonight across parts of the northern/central Plains and Upper
Midwest, and parts of southern New York into the Mid-Atlantic. Large
hail and damaging winds should be the main threats.

...20Z Update...
Only minor changes were made with this update. The MRGL Risk was
expanded slightly southward into northwest KS, where an evolving
storm and additional towering cumulus will pose a risk of isolated
large hail and locally severe gusts -- aided by an elongated
hodograph (around 30 kt of effective shear) and sufficient buoyancy.

In the northern/central Plains, some consideration was given to
adding 30-percent wind probabilities in parts of southeast SD,
northeast NE, and northwest IA. Here, guidance is in good agreement
that an upscale-growing cluster will pose a relatively greater
severe-wind risk. However, given the late expected timing, higher
probabilities were withheld at this time.

For details on the near-term severe risk, see MCDs 2184 and 2185.

..Weinman.. 09/01/2026

.PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Sep 01 2026/

...Mid-Atlantic/Southern New York...
A mid/upper-level anticyclone will remain centered over the TN
Valley/Mid-South today, with a mid-level shortwave trough forecast
to move eastward across Ontario through the period. In between these
features, a belt of enhanced west-northwesterly flow will exist
across the Great Lakes into the Mid-Atlantic. Latest surface
observations show a front draped from northwest to southeast across
southern NY/New England, with cloud cover and precipitation ongoing
across these areas. Current expectations are for destabilization to
occur along/south of the front through the afternoon, with modestly
steepened mid-level lapse rates present across MI (reference 12Z
observed APX/DTX soundings) forecast to advect southeastward across
the Mid-Atlantic. Moderate to strong instability will likely develop
by mid afternoon across PA/NJ, with 30-40 kt of deep-layer shear
fostering updraft organization.

While there is still some uncertainty regarding overall convective
development and evolution this afternoon/evening owing to nebulous
large-scale ascent, most high-resolution guidance develops isolated
to widely scattered thunderstorms along/south of the front,
particularly over eastern PA into NJ and vicinity. Supercells with a
severe hail/wind threat will be possible initially, and enough
low-level shear may exist near the front for a tornado or two as
well. Whether convection can grow upscale into one or more clusters
also remains uncertain. But if this occurs, then the threat for
damaging winds may increase late this afternoon into the evening
given the rather favorable environment forecast.

...Northern/Central Plains into the Upper Midwest/Great Lakes...
A mid-level shortwave trough over the northern/central Rockies and
adjacent High Plains this morning will translate northeastward today
over the northern/central Plains. A moist and unstable airmass will
reside along/south of a front forecast to extend generally west to
east across parts of southern SD/northern NE into southern
MN/northern IA. Robust thunderstorm development appears increasingly
likely by 21-23Z across north-central NE as large-scale ascent
preceding the shortwave trough overspreads the destabilizing warm
sector. Latest NAM/RAP forecast soundings across this region show up
to 1500-2500 J/kg of MLCAPE and strong deep-layer shear, which will
likely support supercells initially. With steepened low/mid-level
lapse rates and elongated/nearly straight hodographs at mid levels
depicted, some potential for 2+ inch hail may exist with these
supercells. A tornado or two also appears possible as low-level
shear gradually increases after 02/00Z. With time, a bowing cluster
is expected to develop across eastern SD/northeast NE this evening,
and subsequently track eastward across southern MN/northern IA with
a severe/damaging wind threat overnight. Some risk for damaging
winds and hail may continue into early Wednesday morning across
parts of WI and Lower MI as well.

...Coastal Southeast Texas/Southwest Louisiana...
Tropical Storm Edouard will continue tracking northwestward today,
per latest NHC forecasts. Some enhancement to the low-level wind
field and hodograph is noted on the latest VWP and 15Z special
observed sounding from KLCH. This may support transient updraft
rotation with any cells on the north to northeast side of Edouard's circulation, and a brief tornado or two may occur this
afternoon/evening across parts of coastal southeast TX/southwest LA
as filtered diurnal heating supports modest destabilization.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 2 01:01:20 2026

ACUS01 KWNS 020101
SWODY1
SPC AC 020059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Tue Sep 01 2026

Valid 020100Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS AND MIDWEST AS WELL AS THE MID ATLANTIC...

...SUMMARY...
Scattered strong to severe thunderstorms remain likely into tonight
across parts of the northern/central Plains and Upper Midwest, and
parts of southern New York into the Mid-Atlantic. Large hail and
damaging winds should be the main threats.

...Southern NY/The Mid Atlantic...
A mid-level shortwave trough and enhanced west-northwesterly flow
were observed from the Northeast/Mid Atlantic States to the lower
Great Lakes this evening. A front was draped from northwest to
southeast across southern NY/New England, with numerous showers and
storms ongoing along and south of it this evening. The air mass here
is unstable and moderately sheared which is supporting organized
supercells and short linear segments. Damaging gusts remain likely
through this evening, along with some hail and perhaps a brief
tornado, especially near the from across southeastern PA and NJ
where low-level sear is maximized. Convection should eventually
begin to weaken with the loss of diurnal heating and as it
approaches the coast later this evening.

...Central Plains and Midwest...
Several supercells have developed ahead of a weak surface low along
a stalled front from NE into SD. A very unstable air mass (MLCAPE of
3000+ J/kg) is in place and extended downstream of the cluster
across eastern SD, northern IA and southern MN. A belt of strong
mid-level westerly flow along the front will continue to support
organized storms. Upscale growth is possible this evening with one
or more clusters or an MCS expected to eventually develop and track
across portions of northern IA and far southern MN. This will pose a
threat for severe wind gusts and perhaps a tornado along the front
through tonight.

Farther southwest along the surface lee trough, scattered high-based
storms were ongoing in eastern CO and western KS. Buoyancy and shear
are much weaker, but steep lapse rates and T/TD spread of 30-40
degrees could support a sporadic severe gusts with these storms
before they weaken near sunset.

...Great Lakes...
A secondary mid-level vort max and upper low, currently over the
western Great lakes, may serve as a focus for additional storm
development tonight across eastern WI and lower MI. The eastern
portions of the quasi stationary front remain very warm and
unstable. As ascent from the upper low/shortwave approach after
midnight, they may support a modest enhancement of the southwestern
low-level jet. Warm advection at the nose of this feature could
allow for a cluster of thunderstorms to develop and intensify. The
large elevated buoyancy and 40-50 kt westerly flow would favor a
risk for hail and damaging gusts before moving into southern ON by
12z Wed. However, confidence in how this scenario evolves remains
low and only 5% wind/hail probabilities will be maintained given the uncertainty in storm development.

...Coastal Southeast Texas/Southwest Louisiana...
Tropical Storm Edouard will continue tracking northwestward across
southeast TX and southwest LA per latest NHC forecasts. Some
enhancement to the low-level wind field and hodographs has been
noted in outer bands along the northern portions of the circulation.
This may support transient updraft rotation with any cells. A brief
tornado or two may occur across parts of coastal southeast
TX/southwest LA through tonight as the system weakens.

..Lyons.. 09/02/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 2 05:59:28 2026

ACUS01 KWNS 020559
SWODY1
SPC AC 020557

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Wed Sep 02 2026

Valid 021200Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
AND CENTRAL MT AND FROM THE LOWER GREAT LAKES TO THE MID ATLANTIC...

...SUMMARY...
Severe thunderstorms are possible across portions of the eastern
Great Lakes to the Mid-Atlantic today and tonight. Damaging wind
gusts are the main threat, though some large hail and a few
tornadoes may also occur. Scattered severe gusts and more sporadic
occurrences of large hail appear possible from the northern Rockies
into northern High Plains Wednesday afternoon into night.

...Eastern Great Lakes, Mid Atlantic...
Several low-amplitude impulses embedded within a belt of moderate
mid-level northwest flow of 40-60 kt will move from the lower Great
Lakes into the northeast and Mid Atlantic today and tonight. A
surface low over James bay will trail a slow moving cold front to
the southwest across lower ON, the lakes and into MI/OH with a
second backdoor front stalled across the eastern Hudson Valley and
southern new England. Within the warm sector, a very moist air mass
will be in place over much of the Northeast contributing to large
buoyancy and broad, but uncertain potential for severe thunderstorms
much of the day.

A complex convective scenario is expected across the region
modulated by several rounds of thunderstorms beginning early this
morning. Convection associated with a lead shortwave trough exiting
southern ON will likely support scattered storms along the front
across the lower Great Lakes and NY this morning. Isolated large
hail and damaging winds are possible with these storms as they move southeastward and encounter a gradually destabilizing air mass
across southern PA and possibly into VA/MD.

Air mass recovery is expected behind this initial condition as the
primary upper trough moves from WI and lower MI into western NY/PA
later in the afternoon. Steep mid-level lapse rates of 7-7.5 C/km
atop boundary layer dewpoints in the upper 60s to low 70s will aide
in destabilization with upwards of 2000-3000+ J/kg of MLCAPE by
afternoon from lower MI into western parts of NY and PA. Storm
development is expected ahead of the approaching trough and cold
front as well as on any residual outflow from the morning storms. A
mix of supercells and line segments is expected with all hazards
possible.

A greater tornado risk may evolve in the evening across southern NY
and central PA, contingent upon air mass recovery in the wake of the
prior storms and presence of a more supercellular mode. NAM/RAP
forecast soundings do show some elongation of low-level hodographs,
and any modifying old pool or outflow boundary could further enhance
low-level shear profiles favorable for tornadoes. Higher tornado
probabilities were considered, but uncertainty on the aforementioned
factors remains large.

...MT/ND...
A compact but strong shortwave trough is forecast to move rapidly
northeastward from the Great Basin to the northern Rockies today and
tonight. 35-50 kt mid-level flow will accompany this feature and
overspread a modestly moist, but warm and unstable air mass across
much of central and eastern MT. Ascent from the approaching
shortwave trough will aid in the development of thunderstorms across
the higher terrain of western MT through the afternoon. Despite
modest buoyancy, steep lapse rate profiles and a deep, well-mixed
boundary layer, will enhance severe-wind-gust potential with these
storms. 30-40 kt of deep-layer shear will promote organization and
clustering with some guidance showing a fast-moving line developing
and moving northeastward through the later afternoon/early evening.
Scattered severe gusts are likely, with peak intensity of 65-80 mph
possible.

Additional storms are possible across portions of eastern MT into
the evening within a zone of warm advection along a nocturnally
strengthening low-level jet. Isolated large hail appears to be the
primary hazard with those storms.

...WY...
Some model guidance shows high-based showers and thunderstorms
developing near the southern fringes of the northern Rockies trough
across WY this afternoon. Modest low-level moisture/buoyancy may
limit convective intensity, but sporadic strong outflow gusts are
possible given a very deeply mixed boundary layer.

...Mid MO Valley into IA and southern MN...
An intensifying low-level jet will likely support an increase in
thunderstorms late this evening/overnight across the MO valley and
parts of the Midwest. Moderate to strong elevated instability and
sufficient vertical shear may exist for a few stronger storms
capable of marginal severe hail. However, overall forcing for ascent
is modest and with building mid-level heights, confidence in a
broader organized severe threat is low.

..Lyons/Wendt.. 09/02/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Sep 2 12:25:22 2026

ACUS01 KWNS 021225
SWODY1
SPC AC 021223

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0723 AM CDT Wed Sep 02 2026

Valid 021300Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHEAST STATES...AND ACROSS PARTS OF MONTANA...

...SUMMARY...
Severe thunderstorms are possible across portions of the eastern
Great Lakes to the Mid-Atlantic today and tonight. Damaging wind
gusts are the main threat, though some large hail and a few
tornadoes may also occur. Scattered severe gusts and more sporadic
occurrences of large hail appear possible from the northern Rockies
into northern High Plains today into night.

...Northeast States...
A complex but potentially active convective day is in store for
parts of the northeast US today. A fast-moving MCS and associated
mid-level shortwave trough is over Lake Michigan. This system is
forecast to track rapidly eastward across Lower MI and southwest ON
this morning before emerging into western NY/PA this afternoon. A
consensus of overnight CAM solutions indicate this will be the focus
for strong-severe thunderstorms that track east-southeastward during
the afternoon and evening toward the Mid-Atlantic coast. Ample
low-level moisture is present in this corridor. This along with
daytime heating well into the 80s and steep low-level lapse rates
will favor damaging wind gust potential in the strongest storms. A
north-south surface boundary is expected to lie from central NY into east-central PA this afternoon, where low-level shear will be
locally enhanced to pose some risk of a few tornadoes.

The primary uncertainty for a more widespread severe event today is
the presence of considerable morning convection currently over
northwest PA and western NY. These storms are well-ahead of the
main forcing feature, and decrease confidence in significant
destabilization over the primary risk area this afternoon. These
early storms may pose a damaging wind and hail risk through the day,
especially after a few hours of heating.

...MT...
Scattered high-based thunderstorms are expected to develop over the
mountains of southwest MT this afternoon. Strong winds aloft and
steep low-level lapse rates will aid in the risk of damaging wind
gusts as the activity spreads northeastward through the early
evening.

...CO/WY...
Scattered afternoon thunderstorms are expected to develop over the
mountains of northern/western CO and southern WY. This activity
will spread northeastward into eastern WY/western NE where
inverted-v thermodynamic profiles are expected with 40-50 t-td
spreads. This may result in locally damaging wind gusts.

..Hart/Dean.. 09/02/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Sep 2 16:31:28 2026

ACUS01 KWNS 021630
SWODY1
SPC AC 021628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed Sep 02 2026

Valid 021630Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN NEW YORK...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
MONTANA...

...SUMMARY...
Scattered to numerous severe thunderstorms are likely across parts
of the Great Lakes to the Mid-Atlantic this afternoon through
tonight. Damaging winds are the main threat, though some large hail
and a few tornadoes may also occur. Scattered severe gusts and
isolated large hail appear possible over the northern Rockies/High
Plains this afternoon and evening.

...Lower Michigan into the Mid-Atlantic...
An ongoing cluster across south-central PA has a well established
cold pool and a history of producing damaging winds across
western/central PA. This convection is expected to continue moving
quickly southeastward through the afternoon across parts of
MD/DC/northern VA and vicinity. There is still some uncertainty on
whether this cluster will be able to maintain intensity with
southward extent into the Mid-Atlantic, as it becomes increasingly
removed from the stronger forcing aloft/mid-level flow over the
Great Lakes into NY. Still, a differential heating zone remains
apparent along/near the Chesapeake Bay per recent visible satellite
imagery and surface observations. The cluster should tend to remain
on the warm side of this boundary, with steepening low-level lapse
rates developing as daytime heating continues to destabilize the
downstream airmass. Scattered damaging winds will likely remain a
threat with these thunderstorms as they track across the southern
Mid-Atlantic before eventually weakening.

In the wake of this late morning/early afternoon activity, it
appears likely that robust destabilization will occur across parts
of lower MI into western NY. 12Z observed soundings from APX/DTX/BUF
showed moderate to very strong MUCAPE and modestly steepened
mid-level lapse rates with an EML. This favorable airmass will
spread eastward through the day in tandem with a mid-level shortwave
trough and 50-60 kt mid-level jet also advancing eastward over the
Great Lakes and ON. Even with some cloud cover present, moderate to
strong instability will likely be in place across western NY by late
afternoon, to the west of a differential heating zone/front.
Thunderstorms are expected to develop along/ahead of a cold front
from parts of southeast Lower MI to the lower Great Lakes, with 50+
kt of deep-layer shear supporting organized updrafts. A mix of
supercells and multicells will likely pose a threat for both severe
hail and scattered to numerous damaging winds. Sufficient low-level
shear should also be present to support a few tornadoes, with some
chance for a strong tornado this evening if a supercell mode can be
maintained across western NY and vicinity. Confidence has increased
in a corridor of greater severe/damaging wind potential late this afternoon/evening across parts of western NY, where an Enhanced Risk
has been introduced.

...Northern Rockies/High Plains...
High-based thunderstorms have already developed over the higher
terrain of central ID this morning. Enhanced winds aloft associated
with a northeastward-ejecting mid-level shortwave trough and steep
low-level lapse rates will support a risk for scattered
severe/damaging winds as this activity spreads northeastward across
MT this afternoon and evening. Occasional 75+ mph gusts may occur,
even though instability should remain weak. Isolated thunderstorms
may also develop later this evening/tonight in a low-level warm
advection regime across eastern MT into western ND, with some hail
threat.

...Eastern Utah into the Central Rockies/High Plains...
Thunderstorms are expected to increase in coverage this afternoon
over eastern UT into the higher terrain of northern/western CO and
southern WY. This activity will spread northeastward into eastern
WY/western NE where a very deep/well-mixed boundary layer should
support locally severe gusts.

..Gleason/Moore.. 09/02/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Sep 2 20:16:00 2026

ACUS01 KWNS 022002
SWODY1
SPC AC 022000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Wed Sep 02 2026

Valid 022000Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN NEW YORK...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
MONTANA...

...SUMMARY...
Scattered to numerous severe thunderstorms are likely across parts
of the Great Lakes to the Mid-Atlantic this afternoon through
tonight. Damaging winds are the main threat, though some large hail
and a few tornadoes may also occur. Scattered severe gusts and
isolated large hail appear possible over the northern Rockies/High
Plains this afternoon and evening.

...20Z Update...
The Enhanced Risk in NY was expanded slightly eastward, driven by
45-percent wind probabilities. Here, temperatures are gradually
warming into the upper 70s to lower 80s (higher than earlier
guidance suggested). This will yield a corridor of moderate
surface-based buoyancy ahead of developing storms this afternoon.
Strong deep-layer shear oriented favorably to an expected cluster of
storms and the destabilizing air mass should support a swath of wind
damage (supported by the latest time-lagged HRRR/RRFS ensemble
guidance). For additional details, see MCD 2201.

Farther west, severe probabilities were trimmed behind a strongly
forced, northeastward-moving band of convection in the northern
Rockies. For details on the near-term severe threat, see MCD 2200
and Severe Thunderstorm Watch 644.

..Weinman.. 09/02/2026

.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Sep 02 2026/

...Lower Michigan into the Mid-Atlantic...
An ongoing cluster across south-central PA has a well established
cold pool and a history of producing damaging winds across
western/central PA. This convection is expected to continue moving
quickly southeastward through the afternoon across parts of
MD/DC/northern VA and vicinity. There is still some uncertainty on
whether this cluster will be able to maintain intensity with
southward extent into the Mid-Atlantic, as it becomes increasingly
removed from the stronger forcing aloft/mid-level flow over the
Great Lakes into NY. Still, a differential heating zone remains
apparent along/near the Chesapeake Bay per recent visible satellite
imagery and surface observations. The cluster should tend to remain
on the warm side of this boundary, with steepening low-level lapse
rates developing as daytime heating continues to destabilize the
downstream airmass. Scattered damaging winds will likely remain a
threat with these thunderstorms as they track across the southern
Mid-Atlantic before eventually weakening.

In the wake of this late morning/early afternoon activity, it
appears likely that robust destabilization will occur across parts
of lower MI into western NY. 12Z observed soundings from APX/DTX/BUF
showed moderate to very strong MUCAPE and modestly steepened
mid-level lapse rates with an EML. This favorable airmass will
spread eastward through the day in tandem with a mid-level shortwave
trough and 50-60 kt mid-level jet also advancing eastward over the
Great Lakes and ON. Even with some cloud cover present, moderate to
strong instability will likely be in place across western NY by late
afternoon, to the west of a differential heating zone/front.
Thunderstorms are expected to develop along/ahead of a cold front
from parts of southeast Lower MI to the lower Great Lakes, with 50+
kt of deep-layer shear supporting organized updrafts. A mix of
supercells and multicells will likely pose a threat for both severe
hail and scattered to numerous damaging winds. Sufficient low-level
shear should also be present to support a few tornadoes, with some
chance for a strong tornado this evening if a supercell mode can be
maintained across western NY and vicinity. Confidence has increased
in a corridor of greater severe/damaging wind potential late this afternoon/evening across parts of western NY, where an Enhanced Risk
has been introduced.

...Northern Rockies/High Plains...
High-based thunderstorms have already developed over the higher
terrain of central ID this morning. Enhanced winds aloft associated
with a northeastward-ejecting mid-level shortwave trough and steep
low-level lapse rates will support a risk for scattered
severe/damaging winds as this activity spreads northeastward across
MT this afternoon and evening. Occasional 75+ mph gusts may occur,
even though instability should remain weak. Isolated thunderstorms
may also develop later this evening/tonight in a low-level warm
advection regime across eastern MT into western ND, with some hail
threat.

...Eastern Utah into the Central Rockies/High Plains...
Thunderstorms are expected to increase in coverage this afternoon
over eastern UT into the higher terrain of northern/western CO and
southern WY. This activity will spread northeastward into eastern
WY/western NE where a very deep/well-mixed boundary layer should
support locally severe gusts.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 3 01:02:38 2026

ACUS01 KWNS 030101
SWODY1
SPC AC 030059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Wed Sep 02 2026

Valid 030100Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS PARTS OF THE SOUTHERN TIER OF NEW YORK INTO NORTHERN AND
CENTRAL PENNSYLVANIA...

...SUMMARY...
Thunderstorms posing a risk for potentially damaging wind gusts may
continue into late evening across parts of the Southern Tier of New
York into northern and central Pennsylvania.

...01Z Update...

...Great Lakes into Mid Atlantic...
To the south of a modest lower/mid-tropospheric cyclone, now
migrating to the east of James Bay, the leading edge of broad
mid-level troughing is in the process of gradually shifting
east-southeast of the lower Great Lakes region. Forcing for ascent
associated with this feature has contributed to the evolution of an
organizing cluster of storms now spreading across western New York
state, ahead of a southward advancing segment of the surface frontal
zone trailing the cyclone. However, in the wake of an early day
convective cluster, appreciable warm sector boundary-layer
instability is becoming confined to a narrowing corridor across the
Allegheny Plateau. As the ongoing convective system continues east-southeastward, and the onset of boundary-layer cooling
progresses, more stable southeasterly near-surface updraft inflow
seems likely to weaken convection and reduce the associated risk for
severe weather as it spreads toward northern Mid Atlantic coastal
areas tonight.

Upstream, convection-allowing guidance suggests that forcing for
ascent associated with lower/mid-tropospheric warm advection may
support renewed widely scattered thunderstorm development overnight.
This is mostly likely to focus near/to the cool side of the
stalling trailing frontal zone on the southern fringe of the
westerlies, across southern portions of the Great Lakes into Upper
Midwest. Aided by modest strengthening of westerly flow in excess
of 30 kt around 850 mb, and steep lapse rates of
lower/mid-tropospheric temperature and potential wet-bulb
temperature, there appears potential for one or two upscale growing
clusters which may pose a risk for severe hail and wind.

...Northern Rockies and adjacent Great Plains...
The risk for severe weather has diminished considerably in the wake
of weakening convection now overspreading the Montana international
border. As the supporting vigorous short wave impulse continues to
pivot north of the border into the Canadian Prairies this evening,
this appears unlikely to change. An isolated strong storm to the east-southeast of Miles City MT does appear supported by updraft
inflow of relatively moist boundary-layer air characterized by
sizable CAPE in excess of 2000 J/kg. However, it is not clear how
long this will be maintained, as inhibition increases with
boundary-layer cooling and perhaps some further warming aloft.

..Kerr.. 09/03/2026

$$

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From COD Weather Processor @1:2320/107 to All on Thu Sep 3 05:55:34 2026

ACUS01 KWNS 030555
SWODY1
SPC AC 030553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Thu Sep 03 2026

Valid 031200Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
TONIGHT ACROSS PARTS OF THE SOUTHERN GREAT LAKES INTO MID ATLANTIC
AND PARTS OF THE NORTHERN GREAT PLAINS...

...SUMMARY...
Scattered strong thunderstorm development is likely today through
tonight, perhaps including a few organizing clusters, posing a risk
for severe wind and hail across parts of the southern Great Lakes
into Mid Atlantic and portions of the northern Great Plains into
Upper Midwest.

...Discussion...
Large-scale mid-level troughing has overspread much of the Pacific
coast through the Rockies. However, models indicate that further
eastward progress will slow, as at least one significant embedded
short wave trough digs offshore and contributes to amplification of
the larger-scale trough near and offshore of the Pacific coast. As
this occurs, downstream ridging is forecast to build across the
northern Great Plains/middle Missouri Valley vicinity by late
tonight, in the wake of a short wave trough now emerging from the
Great Basin and forecast to progress north-northeast of the northern
Rockies through the eastern Canadian Prairies and northwestern
Ontario. Farther east, it appears that mid-level troughing and an
embedded remnant low will slowly dig southeast of western
Quebec/southern Ontario through the northern Atlantic Seaboard.

A surface cold front accompanying the eastern Canadian perturbation
is preceded by considerable ongoing thunderstorm activity
overspreading the northern Mid Atlantic through Lake Erie vicinity.
It appears that an outflow boundary associated with this convection
may become quasi-stationary across parts of southeastern
Pennsylvania/New Jersey, before the initially stalled upstream
front, across southern portions of the Great Lakes vicinity into
Upper Midwest, advances southeast of the lower Great Lakes through
much of the northern Mid Atlantic and upper Ohio Valley by late
tonight.

...Southern Great Lakes into northern Mid Atlantic...
The initially stalled composite outflow boundary and surface front
appear likely to provide the focus for renewed thunderstorm
development later today through tonight. Across the southeastern
Wisconsin through southern Lower Michigan/northern Indiana and Ohio
vicinity, it appears that the corridor of stronger destabilization
along this boundary will remain in relatively close proximity to the
southern fringe of the westerlies. East-southeastward into the
northern Mid Atlantic this remains more unclear.

Regardless, where the seasonably moist boundary layer becomes
strongly heated, thermodynamic profiles a bit further aloft into
mid-levels, aided by elevated mixed-layer air, will remain
characterized by steep lapse rates of temperature and potential
wet-bulb temperature. This will promote the risk for strong
downbursts and evolving cold pools capable of producing strong to
severe wind gusts in developing thunderstorm activity.

There appears potential for one or two organizing clusters across
and east-southeast of the southern Great Lakes region this afternoon
into tonight. It is possible that severe wind probabilities could
still be increased further, once forcing for convection and the
potential negative impacts of early day convection become clearer.

...Northern Great Plains into Upper Midwest...
Forcing for ascent, near and downstream of the short wave emerging
from the Great Basin, appears likely to overspread northern/eastern
North Dakota into northwestern Minnesota during peak boundary-layer
instability this afternoon and evening. Latest convection-allowing
guidance suggests that this will provide support for intensifying
thunderstorm development, which may include a few supercells in the
leading warm advection regime, ahead of a possible upscale growing
cluster near the crest of the building larger-scale mid-level
ridging. Aided by pronounced veering of lower through mid-level
wind fields, deep-layer shear appears conducive to the risk for
large hail, in the presence of thermodynamic profiles with steep
mid-level lapse rates and large CAPE in mid/upper levels. A few
strong downbursts also appear possible.

..Kerr/Wendt.. 09/03/2026

$$

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From COD Weather Processor @1:2320/107 to All on Thu Sep 3 12:14:06 2026

ACUS01 KWNS 031213
SWODY1
SPC AC 031212

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0712 AM CDT Thu Sep 03 2026

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
TONIGHT ACROSS PARTS OF THE SOUTHERN GREAT LAKES INTO MID ATLANTIC
AND PARTS OF THE NORTHERN GREAT PLAINS...

...SUMMARY...
Scattered strong thunderstorm development is likely today through
tonight, perhaps including a few organizing clusters, posing a risk
for severe wind and hail across parts of the southern Great Lakes
into Mid Atlantic and portions of the northern Great Plains into
Upper Midwest.

...PA to Delmarva...
A broad upper ridge remains over the TN Valley, with fast zonal flow
stretching across the Great Lakes into the Mid-Atlantic region.
Multiple clusters of thunderstorms are ongoing this morning over
western PA and northern MD. These storms will progress
southeastward today across an air mass affected by storms last
evening, where there is uncertainty how much destabilization can
occur. Damaging winds will be possible in those areas where
sufficient heating can occur, especially by early afternoon.

...WI to PA...
A common scenario in recent CAM solutions is that a mid-level speed
max associated with convection over MN/IA will track across WI and
into Lower MI by mid/late afternoon. Morning convection will result
in an outflow boundary from southeast WI into southern Lower MI,
likely providing the focus for rapid afternoon thunderstorm
development. Ample low-level moisture/CAPE and favorable westerly
flow aloft suggest an initial risk of supercells, but increasing
linear organization with time. Storms will track into northern
IN/OH by late afternoon, and eventually into western NY/PA this
evening. Damaging wind gusts are the primary concern with this
activity.

...ND/MN...
Morning water vapor imagery suggests a strong shortwave trough
lifting northeastward across WY. This feature will move into the
Dakotas today, aiding the development of intense thunderstorms over
eastern ND by mid-afternoon. Initial supercells will be capable of
large hail and a tornado or two. Activity will likely persist
through much of the evening, tracking eastward across parts of
northern/central MN and perhaps into northern WI. Damaging winds
and hail would be the main concerns during that period.

..Hart/Dean.. 09/03/2026

$$

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From COD Weather Processor @1:2320/107 to All on Thu Sep 3 16:42:32 2026

ACUS01 KWNS 031642
SWODY1
SPC AC 031640

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1140 AM CDT Thu Sep 03 2026

Valid 031630Z - 041200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
OHIO AND WESTERN PENNSYLVANIA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST AND GREAT LAKES TO MID-ATLANTIC...

...SUMMARY...
Scattered strong/severe thunderstorms are expected through tonight,
including a few organizing clusters, posing a risk for severe wind
and hail across parts of the southern Great Lakes into Mid Atlantic
and portions of the northern Great Plains to the Upper Midwest.

...Lake Michigan/upper Ohio River Valley/Northeast...
Several clusters of storms are ongoing at midday across the Lake
Michigan vicinity and lower Michigan, including a smaller lead
cluster entering Ontario, while other convection farther
east-southeast has weakened/diminished across southern
Pennsylvania/Maryland. Regarding the easternmost activity, steady
air mass recovery/diminishing cloud cover appears likely, with ample
insolation across the Northeast along/south of the primary synoptic
front including much of Pennsylvania.

Available regional 12z observed soundings/RAOBs sampled a belt of
moderately strong northwesterly flow aloft that overlies the primary
frontal zone, with moderate to locally strong destabilization
expected outside of the ongoing convection. Some initial supercells
are possible, but more prevalent will be the possibility of
upscale-growing linear bands/clusters, potentially with multiple
rounds of strong/severe convection this afternoon into tonight with
wind damage. This currently appears most probable across northern
Ohio into Pennsylvania.

...Upper Midwest - eastern North Dakota/northern Minnesota...
A slow-moving linear cluster of occasionally severe storms may
persist and gradually accelerate east and maybe eventually
east-southeastward today, potentially becoming more surface based by
later in the afternoon as it parallels the immediate north side of a
surface frontal zone. This development is being influenced by a northeastward-transitioning shortwave trough along the international
border, with a belt of strong mid/high-level winds extending
eastward across the northern half of Minnesota toward the Lake
Superior vicinity.

A mixed convective mode seems probable, with a prominent
quasi-linear mode but also the possibility of south-end
semi-discrete development including supercells. Large hail and
damaging winds are the primary hazards, but some tornado risk may
exist as well. One or more clusters may persist east-southeastward
across the region this evening.

..Guyer/Moore.. 09/03/2026

$$

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From COD Weather Processor @1:2320/107 to All on Thu Sep 3 19:57:54 2026

ACUS01 KWNS 031957
SWODY1
SPC AC 031955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Thu Sep 03 2026

Valid 032000Z - 041200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
OHIO AND WESTERN PENNSYLVANIA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST AND GREAT LAKES TO MID-ATLANTIC...

...SUMMARY...
Scattered strong/severe thunderstorms are expected through tonight,
including a few organizing clusters, posing a risk for severe wind
and hail across parts of the southern Great Lakes into Mid Atlantic
and portions of the northern Great Plains to the Upper Midwest.

...20Z Update...

Minor adjustments have been made to the outlook to account for
recent convective trends and the latest high-resolution forecast
guidance. Portions of the Slight Risk in North Dakota have been
trimmed behind the ongoing convective complex that has since moved
into northern Minnesota, given the trailing airmass has stabilized
and is less likely to see additional convective development.
Additionally, the Marginal Risk was expanded northward from
Wisconsin into portions of Upper Michigan to account for recent
guidance trending northward with the overnight convective complex
and its associated damaging-wind threat. Otherwise, the previous
forecast remains unchanged and on-track for this evening.

..Halbert/Weinman.. 09/03/2026

.PREV DISCUSSION... /ISSUED 1140 AM CDT Thu Sep 03 2026/

...Lake Michigan/upper Ohio River Valley/Northeast...
Several clusters of storms are ongoing at midday across the Lake
Michigan vicinity and lower Michigan, including a smaller lead
cluster entering Ontario, while other convection farther
east-southeast has weakened/diminished across southern
Pennsylvania/Maryland. Regarding the easternmost activity, steady
air mass recovery/diminishing cloud cover appears likely, with ample
insolation across the Northeast along/south of the primary synoptic
front including much of Pennsylvania.

Available regional 12z observed soundings/RAOBs sampled a belt of
moderately strong northwesterly flow aloft that overlies the primary
frontal zone, with moderate to locally strong destabilization
expected outside of the ongoing convection. Some initial supercells
are possible, but more prevalent will be the possibility of
upscale-growing linear bands/clusters, potentially with multiple
rounds of strong/severe convection this afternoon into tonight with
wind damage. This currently appears most probable across northern
Ohio into Pennsylvania.

...Upper Midwest - eastern North Dakota/northern Minnesota...
A slow-moving linear cluster of occasionally severe storms may
persist and gradually accelerate east and maybe eventually
east-southeastward today, potentially becoming more surface based by
later in the afternoon as it parallels the immediate north side of a
surface frontal zone. This development is being influenced by a northeastward-transitioning shortwave trough along the international
border, with a belt of strong mid/high-level winds extending
eastward across the northern half of Minnesota toward the Lake
Superior vicinity.

A mixed convective mode seems probable, with a prominent
quasi-linear mode but also the possibility of south-end
semi-discrete development including supercells. Large hail and
damaging winds are the primary hazards, but some tornado risk may
exist as well. One or more clusters may persist east-southeastward
across the region this evening.

$$

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From COD Weather Processor @1:2320/107 to All on Fri Sep 4 01:02:16 2026

ACUS01 KWNS 040101
SWODY1
SPC AC 040100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Thu Sep 03 2026

Valid 040100Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS PART OF THE MID ATLANTIC INTO MIDDLE OHIO VALLEY...AND ACROSS
PARTS OF THE UPPER MIDWEST...

...SUMMARY...
Scattered strong thunderstorm development, posing mainly a risk for
severe wind and hail, remains possible into the overnight hours
across parts of the Mid Atlantic and Upper Midwest into the Great
Lakes.

...01Z Update...

...Mid Atlantic...
A convectively generated or augmented mid-level perturbation
continues to migrate east-southeastward across the upper Ohio
Valley, toward the northern Mid Atlantic, along the southern fringe
of broadly cyclonic flow overspreading the Northeast. This
continues to provide support for a clustering of stronger convective development currently in a corridor across east central Ohio into
south central Pennsylvania. Although this activity appears to have
waned some in intensity from earlier, updraft inflow emanating from
a more moist environment, along and south of a diffuse remnant
outflow boundary across the central Maryland through Delmarva
Peninsula vicinity, might reinvigorate activity later this evening
into the overnight hours.

...Upper Midwest into Great Lakes region...
Convective evolution into and through the overnight hours remains a
bit unclear. An initial cluster of convection, supported by a short
wave impulse now progressing toward the Minnesota/Ontario border
vicinity and Lake Superior, is undergoing substantial weakening as
inflow becomes more stable to the cool side of a quasi-stationary
frontal zone, which roughly extends from the Red River Valley
through southern Great Lakes region.

Upstream, near the crest of building mid/upper ridging,
lower/mid-tropospheric warm advection is supporting scattered
renewed thunderstorm development across northwestern and west
central Minnesota. Closer to the frontal zone, where the inflow
environment is characterized by moderate to strong instability,
there still appears potential for the evolution of a small
organizing cluster across the Brainerd MN vicinity through mid to
late evening. As this progresses eastward, it is not clear that
this will be maintained overnight. A strengthening southwesterly
low-level jet may focus additional upscale growing thunderstorm
development downstream, across parts of northeastern Wisconsin into
Lower Michigan, but, elevated to the cool side of the frontal zone,
it is not clear that the environment will support more than very
limited potential for severe hail and wind.

..Kerr.. 09/04/2026

$$

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From COD Weather Processor @1:2320/107 to All on Fri Sep 4 05:39:14 2026

ACUS01 KWNS 040539
SWODY1
SPC AC 040537

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1237 AM CDT Fri Sep 04 2026

Valid 041200Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
TONIGHT IN A CORRIDOR ACROSS THE SOUTHERN GREAT LAKES AND
MIDDLE/UPPER OHIO VALLEY INTO MID ATLANTIC...

...SUMMARY...
A couple of organized clusters of thunderstorms may develop across
the southern Great Lakes and mid/upper Ohio Valley today through
tonight, accompanied by the risk for damaging wind gusts. More
widely scattered strong thunderstorms east of the Blue Ridge may
also pose potential for damaging wind gusts this afternoon and
evening.

...Discussion...
Mid/upper flow is forecast to undergo further amplification today
though tonight across southern Canada and the U.S., downstream of
positively tilted large-scale troughing which continues to evolve
offshore of the Pacific coast through Intermountain West. It
appears that this will include building ridging across and north of
the international border, from the Rockies through upper Great
Lakes, to the north of a high centered over the central Great
Plains. Downstream, large-scale troughing is forecast to continue
slowly digging across the northern and middle Atlantic Seaboard. As
it does, it likely will suppress a prominent high initially centered
near the southern Appalachians.

Accompanying the eastern trough, reinforcing surges of cooler
low-level air will continue to overspread portions of the Great
Lakes and Northeast today through tonight. It appears that this
will contribute to a slow south and southwestward progression of the
primary surface front across the Mid Atlantic and through the upper
into middle Ohio Valley.

...Southern Great Lakes into Mid Atlantic...
A moist boundary layer, and remnant plume of relatively steep lower/mid-tropospheric lapse rates, particularly across the Upper
Midwest and southern Great Lakes vicinity into the western slopes of
the Appalachians, may continue to support moderate to strong
potential instability along the quasi-stationary to slow moving
frontal zone. Latest convection allowing guidance suggests that
this front may already be providing a focus for organizing
thunderstorm development across southern Lower Michigan by the
beginning of the period, beneath the favorably sheared southwestern
periphery of the stronger westerlies. As the boundary-layer
destabilizes ahead of it with insolation, it appears that this
activity may intensify further, accompanied by increasing potential
to produce strong to severe wind gusts while propagating
southeastward across parts of northern/eastern Ohio into the
Allegheny Plateau by this afternoon.

It remains unclear whether forcing for ascent and destabilization to
the immediate lee of the Allegheny Mountains and Blue Ridge will
maintain this cluster. However, convection allowing guidance
suggests that the initiation of at least scattered vigorous diurnal thunderstorm activity is probable downstream, closer to and across
the coastal plain, where the environment is likely to be supportive
of a few downbursts with strong to severe surface gusts late this
afternoon into evening.

Late this evening into the overnight hours, downstream of another
short wave perturbation digging to the east of the amplifying
mid-level ridging, there is a notable signal within
convection-allowing and related guidance that forcing for ascent may
support another evolving cluster of storms. This may track close
to, but probably at least a bit to the southwest of, the early day
cluster, from the southern Lower Michigan through Ohio and West
Virginia vicinity.

..Kerr/Chalmers.. 09/04/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 4 12:57:44 2026

ACUS01 KWNS 041257
SWODY1
SPC AC 041255

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 AM CDT Fri Sep 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
GREAT LAKES INTO THE MID-ATLANTIC STATES...

...SUMMARY...
A couple of organized clusters of thunderstorms may develop across
the southern Great Lakes and mid/upper Ohio Valley today through
tonight, accompanied by the risk for damaging wind gusts. More
widely scattered strong thunderstorms east of the Blue Ridge may
also pose potential for damaging wind gusts this afternoon and
evening.

...Southern Great Lakes into Mid Atlantic...
Early-morning satellite imagery shows a deep cyclone over the
Pacific Northwest and upper ridging covering the majority of the
CONUS east of the Rockies. A belt of enhanced mid-level flow
persists between these two features, arcing anticyclonically from
southern CA through the central Rockies and northern Plains into the
Upper Midwest/Upper Great Lakes and eventually through the
Northeast. Recent surface analysis shows a reservoir of low-level
moisture beneath the upper ridging, to the south and east of this
belt of stronger mid-level flow. Much of this area is void of
notable surface features, but a weak front does extend from southern
New England through southern NY, central Lower MI, and central WI to
a weak low over southern MN. A large cluster of showers and
thunderstorms to the south of this front from southern WI into
southern Lower MI. This cluster, which was initiated by warm-air
advection across MN and WI is forecast to continue southeastward
today, likely encountering a diurnally destabilized airmass.

The steeper mid-level lapse rates will remain displaced west of this
region, but ample low-level moisture (i.e. upper 60s/low 70s
dewpoints) coupled with afternoon temperatures from the mid 80s to
mid 90s will still support moderate to strong buoyancy. As such, reintensification and/or new development is anticipated as the
ongoing cluster continues southeastward. Much of this region will be
on the southern fringe of the stronger deep-layer shear, with bowing
line segments as the predominant storm mode. The best overlap
between buoyancy and shear is expected across central and eastern
OH, where a corridor of greater potential for damaging gusts exists.

The threat for damaging gusts will extend into the Mid-Atlantic this
afternoon and evening amid a very warm and moist airmass. Vertical
shear will be weak, but ample moisture (i.e. PW values from 1.8" to
2"), strong buoyancy, and steep low-level lapse rates will support
the potential for strong outflow capable of wind damage. Bowing line
segments will be the primary storm mode here as well.

...Central Plains...
Weak lee troughing could contribute to modest low-level convergence
from western KS across western/central NE into southwest SD.
Dewpoints will likely be in the low to mid 60s within this
convergence zone, and steep mid-level lapse rates will contribute to moderate/strong buoyancy. Even so, warm mid-levels may prevent the
airmass from completely destabilizing. The remaining convective
inhibition, coupled with the presence of large-scale height rises
across the region, casts doubt to whether successful convective
initiation will occur. Any mature updrafts could result in strong
downdraft, but uncertainty is too high to introduce any
probabilities with this outlook.

..Mosier/Lyons.. 09/04/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 4 16:48:48 2026

ACUS01 KWNS 041648
SWODY1
SPC AC 041646

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1146 AM CDT Fri Sep 04 2026

Valid 041630Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
GREAT LAKES INTO THE MID-ATLANTIC STATES...

...SUMMARY...
A couple of organized thunderstorm clusters are expected to develop
across the southern Great Lakes and mid/upper Ohio Valley today
through tonight, accompanied by the risk for damaging wind gusts.
More widely scattered strong thunderstorms east of the Blue Ridge
may also produce damaging wind gusts this afternoon and evening.

...Midwest/southern Great Lakes to Mid-Atlantic States...
As large-scale pattern amplification occurs, a belt of moderately
strong northwesterly flow aloft will tend to overlie a frontal zone
that extends from southern portions of Minnesota/Wisconsin
east-southeastward to Pennsylvania/New Jersey. That said, ongoing
convection has effectively modified/southward-shunted the effective
front in several areas, and this will be the primary focus for storm intensification/redevelopment this afternoon, as well into the
evening/late night.

The steeper mid-level lapse rates will remain displaced west of the
region, but ample low-level moisture (i.e. upper 60s/low 70s
dewpoints) coupled with afternoon temperatures from the mid 80s to
mid 90s will still support moderate to strong buoyancy near/south of
the effective boundary. General storm re-intensification and/or new
development is anticipated this afternoon, particularly south/ahead
of currently ongoing clusters. Bowing line segments will be the
predominant storm mode, with damaging winds as the most common
hazard.

The threat for damaging wind gusts will extend southeastward into
the Mid-Atlantic this afternoon and evening amid a very warm and
moist airmass. Vertical shear will be weaker with southward extent,
but ample moisture (i.e. PW values from 1.8" to 2"), strong
buoyancy, and steep low-level lapse rates will support the potential
for strong outflow capable of wind damage. Bowing line
segments will be the primary storm mode here as well.

...Southern Wisconsin/southern Lake Michigan vicinity...
The same general meteorological thematic scenario as described in
the prior section applies to this region, and severe probabilities
have been extended westward regionally, albeit for a somewhat conditional/uncertain scenario. A robust reservoir of
moisture/locally extreme buoyancy will exist particularly to the
south of ongoing midday convection. The region will be influenced by
the amplifying upper ridge, but there is at least some possibility
that storm redevelopment/intensification could occur near/east of
the surface triple point and/or near outflow, with some related
severe potential. Development could also occur toward the southern
Lake Michigan vicinity later tonight as isentropic ascent increases near/northeast of the surface boundary.

...North-central Plains/Dakotas...
While perceived severe probabilities remain below 5%, some
strong/sporadic severe potential may exist also South Dakota, far
northern Nebraska and/or southeast North Dakota later today through
late tonight, although confidence in specific meteorological
scenarios remains low.

Weak lee troughing will contribute to modest low-level convergence
from western Kansas across western/central Nebraska into southwest
South Dakota. Dewpoints will likely be in the low to mid 60s F
within this convergence zone, and steep mid-level lapse rates will
contribute to moderate/strong buoyancy. Even so, warm mid-levels may
prevent the airmass from completely destabilizing. The remaining
convective inhibition, coupled with the presence of large-scale
height rises across the region, casts doubt to whether successful
convective initiation will occur. Any mature updrafts could result
in strong downdraft, but uncertainty remains high. Other storm
development could occur tonight, potentially as a byproduct of a
subtle mid-level wave/ongoing convection ongoing across South Dakota
this morning.

..Guyer/Thornton.. 09/04/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 4 20:05:16 2026

ACUS01 KWNS 042005
SWODY1
SPC AC 042003

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0303 PM CDT Fri Sep 04 2026

Valid 042000Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
GREAT LAKES INTO THE MID-ATLANTIC STATES...

...SUMMARY...
A couple of organized thunderstorm clusters are expected to develop
across the southern Great Lakes and mid/upper Ohio Valley through
tonight, accompanied by the risk for damaging wind gusts. More
widely scattered strong thunderstorms east of the Blue Ridge may
also produce damaging wind gusts this evening.

...20Z Update...

The northern portion of the Marginal Risk was expanded westward into
portions of northeastern Iowa to account for recent convective
development associated with a mid-level perturbation visible on
water vapor satellite imagery. An unstable airmass and modest
deep-layer shear will support loosely organized convection, capable
of producing isolated occurrences of 60 MPH winds and 1-inch hail.

Elsewhere, the western portion of the Slight Risk area was expanded
across Illinois, Indiana, and portions of Ohio, where thunderstorms
have developed along a surface boundary and may pose an increased
threat for 55-70 MPH wind gusts and 1-inch hail. See MCDs #2234 and
#2235 for more detail.

Further downstream across North Carolina, the severe wind
probabilities were extended southward to account for recent
convective trends. A corridor of higher wind probabilities was
considered across portions of Virginia, but uncertainty in the
longevity of the convection moving across the Appalachians and
overall convective organization precluded adding additional
highlights at this time.

The 30% wind threat area is expected to see convective development
later this evening, as storms move from the Great Lakes into the
region. There is some uncertainty in the northward extent of the
area owing to the drop off in buoyancy, but continued spread in the high-resolution forecast guidance regarding the timing and placement
of convection precludes additional adjustments at this time.

Convection is also anticipated to develop across portions of
north-central Nebraska into South Dakota during the early morning
hours. These storms could produce isolated occurrences of hail,
though uncertainty in the timing of convective initiation and
maturation suggests this will primarily pose a threat in the Day 2
time frame.

..Halbert/Weinman.. 09/04/2026

.PREV DISCUSSION... /ISSUED 1146 AM CDT Fri Sep 04 2026/

...Midwest/southern Great Lakes to Mid-Atlantic States...
As large-scale pattern amplification occurs, a belt of moderately
strong northwesterly flow aloft will tend to overlie a frontal zone
that extends from southern portions of Minnesota/Wisconsin
east-southeastward to Pennsylvania/New Jersey. That said, ongoing
convection has effectively modified/southward-shunted the effective
front in several areas, and this will be the primary focus for storm intensification/redevelopment this afternoon, as well into the
evening/late night.

The steeper mid-level lapse rates will remain displaced west of the
region, but ample low-level moisture (i.e. upper 60s/low 70s
dewpoints) coupled with afternoon temperatures from the mid 80s to
mid 90s will still support moderate to strong buoyancy near/south of
the effective boundary. General storm re-intensification and/or new
development is anticipated this afternoon, particularly south/ahead
of currently ongoing clusters. Bowing line segments will be the
predominant storm mode, with damaging winds as the most common
hazard.

The threat for damaging wind gusts will extend southeastward into
the Mid-Atlantic this afternoon and evening amid a very warm and
moist airmass. Vertical shear will be weaker with southward extent,
but ample moisture (i.e. PW values from 1.8" to 2"), strong
buoyancy, and steep low-level lapse rates will support the potential
for strong outflow capable of wind damage. Bowing line
segments will be the primary storm mode here as well.

...Southern Wisconsin/southern Lake Michigan vicinity...
The same general meteorological thematic scenario as described in
the prior section applies to this region, and severe probabilities
have been extended westward regionally, albeit for a somewhat conditional/uncertain scenario. A robust reservoir of
moisture/locally extreme buoyancy will exist particularly to the
south of ongoing midday convection. The region will be influenced by
the amplifying upper ridge, but there is at least some possibility
that storm redevelopment/intensification could occur near/east of
the surface triple point and/or near outflow, with some related
severe potential. Development could also occur toward the southern
Lake Michigan vicinity later tonight as isentropic ascent increases near/northeast of the surface boundary.

...North-central Plains/Dakotas...
While perceived severe probabilities remain below 5%, some
strong/sporadic severe potential may exist also South Dakota, far
northern Nebraska and/or southeast North Dakota later today through
late tonight, although confidence in specific meteorological
scenarios remains low.

Weak lee troughing will contribute to modest low-level convergence
from western Kansas across western/central Nebraska into southwest
South Dakota. Dewpoints will likely be in the low to mid 60s F
within this convergence zone, and steep mid-level lapse rates will
contribute to moderate/strong buoyancy. Even so, warm mid-levels may
prevent the airmass from completely destabilizing. The remaining
convective inhibition, coupled with the presence of large-scale
height rises across the region, casts doubt to whether successful
convective initiation will occur. Any mature updrafts could result
in strong downdraft, but uncertainty remains high. Other storm
development could occur tonight, potentially as a byproduct of a
subtle mid-level wave/ongoing convection ongoing across South Dakota
this morning.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 5 00:55:44 2026

ACUS01 KWNS 050055
SWODY1
SPC AC 050053

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0753 PM CDT Fri Sep 04 2026

Valid 050100Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN GREAT LAKES INTO THE MID AND UPPER OHIO VALLEY...

...SUMMARY...
Severe storms capable of scattered occurrences of damaging wind with
gusts up to 70 mph are expected across the southern Great Lakes and
mid/upper Ohio Valley overnight. More isolated severe storms capable
of large hail and severe wind gusts may occur over portions of the
northern Plains. Strong to severe storms with a risk for damaging
wind gusts may persist for another couple of hours in the southern Mid-Atlantic.

...Great Lakes into the Ohio Valley...

Forcing for ascent attendant to a weak mid-level disturbance
cresting the mid-level ridge is contributing to a couple of areas of thunderstorm activity this evening over portions of eastern IA and
central WI. The 00Z DVN sounding is likely representative of the
inflow air mass for these storms, featuring a moist boundary layer
and relatively steep mid-level lapse rates with MLCAPE of around
4000 J/kg. It remains unclear whether a subset of the current storms
will grow upscale into a cold-pool-driven MCS overnight, or whether
additional storms will develop farther to the east across portions
of southern Lake MI and southwest Lower MI in the next few hours.
Either way, there is a consistent model signal for a bowing
convective system to evolve across portions of northeast IN into OH,
along the cool side of a composite surface boundary extending from
central WI through central IN into eastern KY.

Regional VWPs and 00Z soundings indicate the presence of 30-35 kt
northwest winds in the mid levels along the axis of the prospective
MCS track, which will contribute to sufficient deep-layer shear for
cold-pool organization. As such, a corridor of more concentrated
wind damage appears possible along with severe gusts up to 70 mph.

...Northern Plains...

A cluster of mainly elevated thunderstorms is ongoing this evening
over north-central SD, with that activity likely rooted above a warm
capping inversion observed by the 00Z ABR sounding. Additional
storms are expected to develop overnight along a nocturnally
strengthening low-level jet, where warm advection and moisture
transport will be maximized. Mid-level flow and resultant vertical
shear are forecast to weaken overnight owing to the proximity of the
mid-level ridge. However, the presence of steep mid-level lapse
rates and associated moderate to strong instability suggests the
potential for isolated severe storms capable of large hail and
severe wind gusts. As such, 5% wind and hail probabilities have been
included in this forecast update.

...Southern Mid-Atlantic...

Clusters of strong to severe thunderstorms ongoing over portions of
southeast VA into north-central and northeast NC will remain capable
of mainly damaging wind gusts for the next hour or two. Thereafter,
storms are expected to gradually weaken as the boundary layer
stabilizes.

..Mead.. 09/05/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sat Sep 5 05:24:56 2026

ACUS01 KWNS 050524
SWODY1
SPC AC 050522

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1222 AM CDT Sat Sep 05 2026

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE OHIO VALLEY INTO THE SOUTHERN MID-ATLANTIC AND CAROLINAS...

...SUMMARY...
Severe thunderstorms capable of mainly damaging gusts are possible
across portions of the Ohio Valley into southern Mid-Atlantic and
Carolinas on Saturday afternoon and evening. Isolated occurrences of
large hail and severe wind gusts also appear possible over parts of
the northern and central Plains Saturday into Saturday night.

...Synopsis...

A prominent mid-level ridge will persist over the central CONUS
between upper lows over the Pacific Northwest and the Gulf of St.
Lawrence into NB/NS. Several weak disturbances (some of convective
origin) will progress through the periphery of the ridge, serving as
foci for thunderstorm development. At the surface, an area of low
pressure is forecast over the western Dakotas with an associated
boundary --the location of which may be modified by convective
outflow-- extending into the OH Valley and southern Mid-Atlantic.
The eastern extension of the boundary will begin to push south as a
cold front Saturday afternoon into night as high pressure builds
into the Great Lakes.

...Ohio Valley into the Carolinas...

A mature to decaying MCS is expected to be ongoing 12Z Saturday over
portions of the middle to upper OH Valley, aided by a subtle
mid-level disturbance/possible MCV. There is considerable
variability across the 00Z convection-allowing models in the
longevity and extent of the convective system over the central
Appalachians into southern Mid-Atlantic through the remainder of the
morning. Should the MCS remain intact, isolated occurrences of
damaging wind are possible.

Renewed thunderstorm development is likely by afternoon along the
residual MCS cold pool and/or synoptic front as temperatures in the
90s to around 100 combine with boundary-layer dewpoints in the low
to mid 70s to yield MLCAPE up to 2000-3000+ J/kg with steepening
low-level lapse rates. Additionally, the models indicate some
enhancement of mid-level winds in association with the
disturbance/MCV moving through the southern Mid-Atlantic during the
afternoon, which may yield more organized multicells and line
segments with the predominant hazard being damaging wind gusts into
the evening.

Farther to the west, additional strong to severe storms appear
possible along and ahead of the composite boundary from the vicinity
of the OH River south into the Cumberland Plateau where widely
scattered damaging wind gusts also appear possible.

...Northern and Central Plains...

A band of elevated thunderstorms is expected to be ongoing 12Z
Saturday, centered over eastern SD. That activity is expected to
diminish through the morning with the cessation of the nocturnal
low-level jet; however, isolated occurrences of large hail and
severe wind gusts appear possible prior to dissipation. In the wake
of the early-day storms, the presence of steep low/mid-level lapse
rates and richer boundary-layer moisture with eastward extent will
contribute to a moderately to strongly unstable air mass by
afternoon with MLCAPE of 2000-3500+ J/kg.

Nebulous forcing for ascent and capping relating to the proximity of
the mid-level ridge axis lead to uncertainty in the specific details
regarding the location and extent of surface-based thunderstorm
development during the afternoon into evening. However, the presence
of the surface low, outflow-modified surface front, and a lee trough
over the High Plains will be candidates for storm development. The
strongest deep-layer shear (30-40 kt) is forecast to the north of
the surface low and composite boundary over ND and northern SD into
western MN where a conditional risk of supercells capable of large
hail and severe wind gusts exists. Elsewhere, high-based pulse and
multicell storm modes appear possible with the primary hazard being widely-spaced severe wind gusts.

The isolated severe threat may persist into the overnight hours in
the vicinity of a nocturnally strengthening low-level jet.

...Western Montana...

A belt of enhanced mid/upper-level flow will exist across the
region, to the east of the upper low over the Pacific Northwest.
Heating along the high terrain coupled with the possible influence
of a weak mid-level disturbance is expected to support an increase
in high-based showers and a few thunderstorms during the afternoon
and evening. While lapse rates will be steep with strong deep-layer
shear, the absence of appreciable moisture will limit MLCAPE to
generally less than 250 J/kg. As such the potential for severe wind
gusts is currently too low to warrant 5% wind probabilities.

..Mead/Chalmers.. 09/05/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 5 12:56:50 2026

ACUS01 KWNS 051256
SWODY1
SPC AC 051254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Sat Sep 05 2026

Valid 051300Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE OHIO VALLEY INTO SOUTHERN MID-ATLANTIC AND CAROLINAS...

...SUMMARY...
Severe thunderstorms capable of mainly damaging gusts are possible
across portions of the Ohio Valley into southern Mid-Atlantic and
Carolinas this afternoon and evening. Isolated occurrences of large
hail and severe wind gusts also appear possible over parts of the
northern and central Plains today into tonight.

...Ohio Valley into the Carolinas...
An MCS continues to progress southeastward towards the central
Appalachians this morning. The outflow has surged well ahead of the
deep convection along the western edge of this MCS, but remains much
closer to the two primary cores of deep convection along the central
and eastern portions of the MCS. General expectation is for this MCS
to continue southeastward across the central Appalachians and into
the Mid-Atlantic, while the westward-progressing outflow stalls and
loses definition.

Currently, the airmass downstream across the Mid-Atlantic is
characterized by dewpoints ranging from the upper 60s across
northern VA into the mid 70s across southeast NC/eastern SC. Strong
heating is anticipated across much of this region today, with high
temperatures ranging from the low 90s over northern to the upper
90s/low 100s across central/eastern SC. These warm and moist surface
conditions will support moderate to strong afternoon buoyancy,
despite poor mid-level lapse rates. Reintensification and/or renewed thunderstorm development is expected as the MCS (and associated
vorticity maximum) interacts with this destabilized airmass. This
region will be along the southerly periphery of a belt of mid-level northwesterlies, and the resulting vertical shear could help
maintain a favorable cold pool/updraft balance needed to maintenance
of a progressive convective line. Guidance varies on whether one
coherent convective line or a series of smaller bowing segments will
develop, but either case would yield a threat for damaging gusts.
Highest probability for damaging gusts is expected across eastern NC
where the best overlap between buoyancy and vertical is expected.

Additional afternoon development is expected farther west, from the
middle OH Valley through Middle TN, where residual outflow will
likely be present with a destabilized airmass. Weak shear should
limit storm organization but isolated damaging gusts are possible.

...Northern and Central Plains...
Elevated thunderstorms have persisted throughout much of the night
from northeast NE across eastern SD. A second area of thunderstorm
activity exists farther norther across north-central ND. An isolated
instance of hail is possible over both of these regions for the next
few hours before thunderstorm intensity wanes in response to the
cessation of the nocturnal low-level jet.

Despite rising heights throughout the day, most guidance suggests
that low-level convergence along both the lee trough and
outflow-modified front in NE will be sufficient for convective
initiation this afternoon. Limited vertical shear and a deeply mixed
boundary layer suggest an outflow-dominant storm mode with the
primary hazard being widely-spaced severe wind gusts.

Relatively higher thunderstorm coverage is possible across the
central High Plains this evening as warm-air advection supports
additional thunderstorm activity. Some clustering of this activity
is possible, but vertical shear will be weak and overall storm
intensity and organization should be modest.

...Western Montana...
A belt of enhanced mid/upper-level flow will extend across the
region, to the east of an upper low over the Pacific Northwest.
Increasing mid-level moisture and forcing for ascent associated with
a weak mid-level disturbance is expected to support an increase in
high-based showers and a few thunderstorms during the afternoon and
evening. Lapse rates will be steep with strong deep-layer shear, but
the absence of appreciable moisture will limit MLCAPE to generally
less than 250 J/kg. As such the potential for severe wind gusts is
currently too low to warrant 5% wind probabilities.

..Mosier/Lyons.. 09/05/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 5 17:00:28 2026

ACUS01 KWNS 051624
SWODY1
SPC AC 051622

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1122 AM CDT Sat Sep 05 2026

Valid 051630Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL APPALACHIANS INTO SOUTHERN VIRGINIA AND THE CAROLINAS...

...SUMMARY...
Strong to severe thunderstorms capable of producing scattered
damaging winds should occur this afternoon/evening across parts of
the central Appalachians into southern Virginia and the Carolinas.
Isolated large hail and severe winds may also occur over parts of
the northern/central Plains through tonight.

...Ohio Valley/Central Appalachians into the Mid-Atlantic and
Carolinas...
An earlier MCS across the OH Valley has weakened as it crossed/moved
eastward over the central Appalachians. The strongest remaining
convective segment is ongoing late this morning across parts of
southwest VA/northeast TN. Robust destabilization is expected to
continue this afternoon downstream of this activity across southern
VA into the Carolinas, with MLCAPE peaking around 2500-3500 J/kg
over central/eastern NC. This region will be on the southern
periphery of modestly enhanced mid-level west-northwesterly flow,
and sufficient deep-layer shear will be present to maintain some
convective organization.

Current expectations are for one or more thunderstorm clusters to
gradually increase in intensity this afternoon as they spread
eastward across southern VA and central/eastern NC, with some
uncertainty whether the ongoing convection will restrengthen, or if
new development will occur along its outflow. Regardless, latest
guidance and observational trends still suggest that a relatively
greater threat for damaging winds should exist this afternoon across central/eastern NC and vicinity, where the greatest thunderstorm
coverage, maxima in MLCAPE/DCAPE, and steepened low-level lapse
rates are forecast. Have therefore introduced higher severe wind
probabilities (30% area) across this region. Isolated hail may also
occur with the strongest cores that can develop, although mid-level
lapse rates are expected to remain rather poor. Severe potential
should gradually wane this evening with the loss of daytime heating,
and as convection moves offshore.

Farther west, outflow from the morning thunderstorms may serve as a
focus for renewed thunderstorm development this afternoon from parts
of the OH Valley southeastward into the TN Valley. This region will
be displaced from the stronger flow aloft present over the Mid-Atlantic/Northeast, with weak deep-layer shear expected. Still,
some risk for isolated damaging winds may exist with any loosely
organized cells/clusters that can develop given the presence of
moderate to locally strong instability.

...Northern/Central Plains...
A highly amplified mid/upper-level ridge will remain anchored over
the central CONUS into south-central Canada through the period, with
generally neutral to weakly rising mid-level heights expected over
the northern/central Plains. Ongoing elevated cells across northern
ND may continue to pose an isolated severe hail threat in the short
term, but weakening low-level warm advection should tend to result
in a further decrease in intensity with this activity. Otherwise,
additional isolated to perhaps widely scattered high-based
thunderstorms may develop this afternoon along/east of a surface lee
trough over the northern/central Plains. While mid-level flow and
related effective bulk shear should remain weak, occasional severe
gusts may still occur with convective downdrafts given a well-mixed
boundary layer. Some risk for hail and gusty winds may also exist
with elevated convection that should eventually develop tonight into
early Sunday morning in a renewed/modest low-level warm advection
regime.

...Western Montana...
To the east of a closed mid-level low over WA/OR, a belt of enhanced southwesterly mid/upper-level winds will extend across the northern
Rockies. Gradually increasing moisture and large-scale ascent aloft
associated with a weak/embedded shortwave trough are expected to
support an increase in isolated thunderstorms this
afternoon/evening. Lapse rates through low/mid levels will be steep
with strong deep-layer shear present, but modest low-level moisture
should limit MLCAPE to generally less than 500 J/kg. The potential
for severe wind gusts still appears too low to justify including 5%
wind probabilities at this time.

..Gleason/Thornton.. 09/05/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 5 20:05:00 2026

ACUS01 KWNS 052002
SWODY1
SPC AC 052000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sat Sep 05 2026

Valid 052000Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS INTO SOUTHEASTERN VIRGINIA...

...SUMMARY...
The threat of strong to severe thunderstorms capable of producing
scattered damaging winds will continue this afternoon/evening across
parts of the Carolinas and southern Virginia. Isolated large hail
and severe winds may also occur over parts of the northern/central
Plains through tonight.

...20Z Update...
Only minor changes were made with this update. The SLGT Risk was
trimmed behind an east-southeastward moving band of convection
moving across the Carolinas. While isolated redevelopment cannot be
entirely ruled out in the wake of this activity, the primary severe
risk will continue spreading eastward to the coast into this
evening.

Farther west, 5-percent hail probabilities were added in parts of
the lower OH Valley. Here, relatively steep deep-layer lapse rates,
around 30 kt of effective shear, and a cellular mode may support
isolated instances of marginally severe hail.

Elsewhere, the previous forecast remains on track.

..Weinman.. 09/05/2026

.PREV DISCUSSION... /ISSUED 1122 AM CDT Sat Sep 05 2026/

...Ohio Valley/Central Appalachians into the Mid-Atlantic and
Carolinas...
An earlier MCS across the OH Valley has weakened as it crossed/moved
eastward over the central Appalachians. The strongest remaining
convective segment is ongoing late this morning across parts of
southwest VA/northeast TN. Robust destabilization is expected to
continue this afternoon downstream of this activity across southern
VA into the Carolinas, with MLCAPE peaking around 2500-3500 J/kg
over central/eastern NC. This region will be on the southern
periphery of modestly enhanced mid-level west-northwesterly flow,
and sufficient deep-layer shear will be present to maintain some
convective organization.

Current expectations are for one or more thunderstorm clusters to
gradually increase in intensity this afternoon as they spread
eastward across southern VA and central/eastern NC, with some
uncertainty whether the ongoing convection will restrengthen, or if
new development will occur along its outflow. Regardless, latest
guidance and observational trends still suggest that a relatively
greater threat for damaging winds should exist this afternoon across central/eastern NC and vicinity, where the greatest thunderstorm
coverage, maxima in MLCAPE/DCAPE, and steepened low-level lapse
rates are forecast. Have therefore introduced higher severe wind
probabilities (30% area) across this region. Isolated hail may also
occur with the strongest cores that can develop, although mid-level
lapse rates are expected to remain rather poor. Severe potential
should gradually wane this evening with the loss of daytime heating,
and as convection moves offshore.

Farther west, outflow from the morning thunderstorms may serve as a
focus for renewed thunderstorm development this afternoon from parts
of the OH Valley southeastward into the TN Valley. This region will
be displaced from the stronger flow aloft present over the Mid-Atlantic/Northeast, with weak deep-layer shear expected. Still,
some risk for isolated damaging winds may exist with any loosely
organized cells/clusters that can develop given the presence of
moderate to locally strong instability.

...Northern/Central Plains...
A highly amplified mid/upper-level ridge will remain anchored over
the central CONUS into south-central Canada through the period, with
generally neutral to weakly rising mid-level heights expected over
the northern/central Plains. Ongoing elevated cells across northern
ND may continue to pose an isolated severe hail threat in the short
term, but weakening low-level warm advection should tend to result
in a further decrease in intensity with this activity. Otherwise,
additional isolated to perhaps widely scattered high-based
thunderstorms may develop this afternoon along/east of a surface lee
trough over the northern/central Plains. While mid-level flow and
related effective bulk shear should remain weak, occasional severe
gusts may still occur with convective downdrafts given a well-mixed
boundary layer. Some risk for hail and gusty winds may also exist
with elevated convection that should eventually develop tonight into
early Sunday morning in a renewed/modest low-level warm advection
regime.

...Western Montana...
To the east of a closed mid-level low over WA/OR, a belt of enhanced southwesterly mid/upper-level winds will extend across the northern
Rockies. Gradually increasing moisture and large-scale ascent aloft
associated with a weak/embedded shortwave trough are expected to
support an increase in isolated thunderstorms this
afternoon/evening. Lapse rates through low/mid levels will be steep
with strong deep-layer shear present, but modest low-level moisture
should limit MLCAPE to generally less than 500 J/kg. The potential
for severe wind gusts still appears too low to justify including 5%
wind probabilities at this time.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 6 00:58:56 2026

ACUS01 KWNS 060058
SWODY1
SPC AC 060056

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 PM CDT Sat Sep 05 2026

Valid 060100Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEAST
COLORADO INTO PARTS OF WESTERN NEBRASKA...INCLUDING THE PANHANDLE...

...SUMMARY...
Widely scattered occurrences of large hail and severe wind gusts are
expected into tonight over northeast Colorado into parts of western
Nebraska, including the Panhandle. Isolated occurrences of large
hail and damaging winds remain possible overnight across a broader
portion of the northern and central Plains. Damaging wind potential
is expected to diminish within the next couple of hours over
portions of Kentucky, Georgia, and South Carolina.

...Northern and Central Plains...

Separate clusters of thunderstorms, including supercells, are
ongoing this evening over the NE Panhandle into northeast CO ahead
of a weak mid-level disturbance moving through WY and north-central
CO. The 00Z LBF sounding sampled relatively steep lapse rates with
MLCAPE of around 2500 J/kg along with a vertically veering wind
profile with around 30 kt of deep-layer shear. As such, expect the
supercell threat to persist for the next hour or two, prior to
storms merging into a larger complex along a nocturnally
strengthening low-level jet. Large hail up to two inches will be the
main hazard in the near-term; however, the potential for severe wind
gusts will become more prevalent if an organized cold pool can
evolve.

Elsewhere, storms are widely scattered across the Dakotas with the
00Z ABR sounding indicating a moderately unstable, but capped air
mass for surface-based parcels. Additional, elevated storms appear
possible overnight along the low-level jet axis with a risk for
isolated occurrence of large hail and damaging wind gusts.

...Central Georgia into southern South Carolina...

Widely scattered thunderstorms are ongoing this evening from south
of Atlanta into southern SC, along an outflow boundary remnant from
storms earlier today. Isolated occurrences of damaging wind gusts
remain possible for the next hour or two before low-level lapse
rates begin to weaken with the loss of daytime heating.

...Kentucky...

A small cluster of thunderstorms has recently intensified south of
the OH River, east of Owensboro, in the vicinity of a weak surface
boundary, and ahead of a weak mid-level disturbance approaching the
area from the north. Regional 00Z soundings indicate the air mass
remains moderately unstable with around 30 kt of deep-layer shear.
The ongoing storms will remain capable of strong wind gusts for the
next hour or so before the boundary layer begins to stabilize.

..Mead.. 09/06/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 6 05:44:02 2026

ACUS01 KWNS 060543
SWODY1
SPC AC 060541

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 AM CDT Sun Sep 06 2026

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN APPALACHIANS INTO THE SAVANNAH RIVER VALLEY AND OVER
PARTS OF WESTERN AND CENTRAL MONTANA...

...SUMMARY...
Widely scattered damaging wind gusts are likely across portions of
the Southeast Sunday afternoon and early evening. Widely scattered
large hail occurrences are expected across portions of western and
central Montana Sunday afternoon and evening. Additional areas at
risk for severe wind and hail are across parts of the Interior West,
over the northern and central High Plains, and from the eastern
Dakotas and western Minnesota into the Ozark Plateau and Gulf Coast
states.

...Synopsis...

A prominent mid-level ridge over the central U.S. is forecast to
weaken during the latter half of the period in response to the
progression of two distinct short-wave troughs and associated wind
maxima through the Interior West. Separate, weaker perturbations
will move through the ridge axis over the northern Plains/mid-MO
Valley region on Sunday, contributing to thunderstorm development in
those areas. Elsewhere, a mid-level disturbance over the OH Valley
Sunday morning is forecast to move into the Cumberland Plateau
vicinity by afternoon, also likely serving as a focus for
thunderstorm development.

At the surface, a lee cyclone will persist over the northern High
Plains, with that feature potentially deepening Sunday night in
response to increasing height falls aloft. High pressure will build
across the Great Lakes, OH Valley, and Northeast with a baroclinic
zone present between those surface features from the mid-MO Valley
through the Ozarks and TN Valley into the Southeast.

...Southern Appalachians into the Savannah River Valley...

Temperatures in the 90s will coincide with boundary-layer dewpoints
in the 70s to yield a moderately to strongly unstable air mass
(i.e., MLCAPE of 2000-3000+ J/kg) by afternoon with steepening
low-level lapse rates. Aided by forcing attendant to the mid-level
disturbance mentioned above, that thermodynamic environment will
support an increase in thunderstorm coverage and intensity through
the afternoon along and ahead of the surface front.

Some increase in mid-level winds may accompany the disturbance with
up to 30 kt of deep-layer shear forecast in the vicinity of the
frontal zone. As such, the potential will exist for longer-lived
multi-cells and line segments capable of damaging wind gusts and
perhaps some large hail into evening.

...Ozark Plateau into the Gulf Coast States...

A similar thermodynamic environment to that previously described is
anticipated ahead of the surface front Sunday afternoon. Generally
weak forcing for ascent and vertical shear are expected to limit the
potential for a more organized severe weather threat. However, the
degree of instability will support briefly intense pulse-type storms
capable of locally damaging wet microbursts during the afternoon and
early evening hours.

...Northern Great Basin into the northern Rockies...

Increasing height falls and strengthening mid/upper-level flow will
overspread the region Sunday afternoon into night ahead of a
vigorous short-wave trough pivoting through the base of the Pacific
Northwest upper low. The strongest instability (i.e., MLCAPE up to
1000-1500 J/kg) is forecast across portions of western into central
MT with stronger capping with eastward extent. The presence of 40-50
kt of deep-layer shear will support supercells capable of mainly
large hail through Sunday evening. While forecast hodographs exhibit considerable curvature/veering winds in the lowest 1-2-km AGL,
stability concerns in the boundary layer may limit severe-wind-gust
and tornado potential.

Weaker instability is forecast from northeast NV and northern UT
into central and eastern ID. However, the presence of steep lapse
rates and kinematics mentioned above may yield a few severe storms
capable of severe wind gusts.

...Northern and central High Plains...

Stronger forcing for ascent is expected to remain to the west and
east of the region through the daylight hours, leading to
uncertainty in storm coverage in the vicinity of the surface low and
lee trough. The 00Z models indicate an increasing potential for at
least isolated thunderstorms from mid-afternoon into evening along
the lee trough. RAP-based forecast soundings show steep lapse rates
and resulting MLCAPE of 1000-2000+ J/kg. The strongest deep-layer
shear of 40-50 kt is forecast across eastern MT into ND with
decreasing magnitudes with southward extent along the lee trough. As
such, a conditional risk for supercells capable of large hail and
severe wind gusts exists. While Marginal Risk wind and hail
probabilities will be maintained with this forecast, an upgrade to
level 2/Slight Risk is possible in subsequent updates.

...Eastern Dakotas and western Minnesota into the lower Missouri
Valley...

Clusters of mainly elevated thunderstorms may be ongoing at 12Z
Sunday, aided by forcing associated with the weak disturbance(s)
cresting the mid-level ridge axis. A subset of the early-day storms
is expected to persist into afternoon with additional storms forming
on the leading edge of more persistent cloud cover, where pockets of
stronger heating and boundary-layer dewpoints in the low/mid 70s
will yield MLCAPE of 1500-2500 J/kg. The 00Z models suggest that
storms will eventually grow upscale into an MCS that tracks south
along or to the immediate cool side of the surface boundary through
portions of the middle and lower MO Valley Sunday afternoon into
evening. It currently appears that deep-layer shear of generally
less than 30 kt and marginally steep mid-level lapse rates may limit
the degree of cold pool organization and a greater/more continuous damaging-wind threat. Nonetheless, the setup appears supportive of
sporadic damaging wind and severe hail occurrences.

..Mead/Chalmers.. 09/06/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 6 12:53:06 2026

ACUS01 KWNS 061252
SWODY1
SPC AC 061251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Sun Sep 06 2026

Valid 061300Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN APPALACHIANS INTO THE SAVANNAH RIVER VALLEY...AND OVER
PARTS OF WESTERN AND CENTRAL MONTANA...

...SUMMARY...
Widely scattered damaging wind gusts are likely across portions of
the Southeast this afternoon and early evening. Widely scattered
large hail occurrences are expected across portions of western and
central Montana this afternoon and evening. Additional areas at risk
for isolated severe wind and hail are parts of the Interior West,
over the northern and central High Plains, and from the eastern
Dakotas and western Minnesota into the Ozark Plateau and Gulf Coast
states.

...Southern Appalachians through coastal SC and GA...
A moist airmass is in place across the region this morning, with
recent surface analysis revealing a reservoir of low to mid 70s
dewpoints. Strong heating is anticipated across this region today,
with afternoon temperatures reaching the low to mid 90s. This strong
heating will destabilize the airmass and contribute to
moderate/strong buoyancy, with MLCAPE around 2000-2500 J/kg likely
during the late afternoon. A subtle shortwave trough will progress
through the northwesterly flow aloft extending over the area,
interacting with this destabilized airmass to support thunderstorm
development. Vertical shear will generally be weak, limiting updraft organization and promoting a predominantly outflow-dominant storm
mode. Even so, steep low-level lapse rates and abundant moisture
will promote the potential for damaging wind gusts with any
longer-lived multi-cells or line segments. Updraft augmentation due
to storm interactions could also result in isolated hail.

...Ozark Plateau into the Gulf Coast States...
A corridor of greater low-level moisture arcs from the Southeast
states through Arkansas and Missouri. Daytime heating will
destabilize this airmass, helping to support thunderstorm
development in areas of low-level confluence. Weak forcing for
ascent and vertical shear are expected to limit storm organization.
However, the degree of instability will support briefly intense
pulse-type storms capable of locally damaging wet microbursts during
the afternoon and early evening hours.

...Eastern Dakotas and western Minnesota into the lower Missouri
Valley...
A linear MCS continues to push eastward across the central Plains
this morning. A notable vorticity maximum has developed within the
northern portion of this line. Its motion appears to be more
northeasterly than the line itself, and new development is occurring
downstream of this vorticity maximum across south-central/southeast
SD and adjacent northeast NE. A corridor of relatively greater
low-level moisture (i.e. dewpoints in the low 70s) exists downstream
of this vorticity maximum and attendant MCS from eastern SD through
western IA and into northern MO. General expectation is for
thunderstorm coverage and intensity to increase later this
morning/early afternoon as the vorticity maximum/remnant MCS
interact with this moist and diurnally destabilizing airmass. Much
of this development is expected to occur along or to the immediate
cool side of the surface boundary that extends through portions of
the middle and lower MO Valley. Occasionally strong updrafts could
result in isolated hail and/or damaging gusts, but the weak
mid-level flow and associated modest deep-layer shear should limit
storm organization and contribute to clustered multicellular mode.

...Northern Plains into the northern/central High Plains...
Modest height falls may begin to impinge on northern/central High
Plains during the early evening as a low-amplitude shortwave trough
moves a belt of stronger southwesterlies just west of the region.
This modest ascent will augment low-level convergence along the lee
trough to support isolated to widely scattered thunderstorm
development where the lingering convective inhibition can be
overcome. This appears most likely across southeast WY and northeast
CO where persistent low-level easterly flow could keep dewpoints in
the 60s. High-based, outflow-dominant storms will support the
potential for isolated strong to severe gusts.

Increasing mid-level flow will support stronger deep-layer vertical
shear farther north (into eastern MT and western ND), but stronger
convective inhibition may linger, casting doubt whether storms will
initiate. If initiation is realized, storm motion could take it into
the more moist and buoyant airmass north of the surface low where
thermodynamic profiles are favorable for large to very large hail.
Will maintain 5% wind/hail probabilities but introduce a CIG1 for
hail given the conditional potential.

...Northern Great Basin into the northern Rockies...
Increasing height falls and strengthening mid/upper-level flow will
spread across the region today ahead of a vigorous shortwave trough
pivoting through the base of a Pacific Northwest upper low.
Thunderstorm development is anticipated over the higher terrain
before then progressing northeastward towards lower elevations.
Deep-layer vertical shear of 40 to 50 kt will support supercells,
with large hail as the primary severe risk. Greater buoyancy is
expected across central MT, but low-level stability will likely
persist across this region as well, potentially limiting the
severe-wind and tornado potential.

Weaker instability is forecast from northeast NV and northern UT
into central and eastern ID. However, the presence of steep lapse
rates and kinematics mentioned above may yield a few severe storms
capable of severe wind gusts.

..Mosier/Lyons.. 09/06/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 6 16:32:26 2026

ACUS01 KWNS 061632
SWODY1
SPC AC 061630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sun Sep 06 2026

Valid 061630Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHEAST...MONTANA...AND NORTH DAKOTA...

...SUMMARY...
Scattered damaging winds should occur across parts of the Southeast
this afternoon/early evening. Scattered large hail is forecast
across portions of Montana and North Dakota this afternoon and
evening. Isolated strong to severe thunderstorms may also occur
today across parts of the northern Great Basin, northern/central
Plains, and Missouri Valley to the Ozarks.

...Southeast/Lower Mississippi Valley...
Recent visible satellite imagery shows mostly clear skies across
GA/SC late this morning, with surface temperatures already in the
mid/upper 80s to low 90s. A weak front is draped from northwest to
southeast from the southern Appalachians to the Atlantic Coast, with
generally low to mid 70s surface dewpoints present to its south.
Continued diurnal heating of this moist airmass will support the
development of moderate to strong instability (greater with
southward/westward extent into GA/AL and north FL). Compared to the
past couple of days, this region will be displaced from the stronger
mid-level west-northwesterly flow present across the
Mid-Atlantic/Northeast. Corresponding deep-layer shear is expected
to remain rather modest (less than 25 kt), with only loosely
organized updrafts forecast. Even with these kinematic limitations,
steepening low-level lapse rates through the afternoon may still
promote isolated to scattered damaging winds with clusters that
develop and spread south-southeastward through the early evening.
Isolated hail may also occur with the more robust cells that can
develop initially. The damaging wind threat should be more isolated
with westward extent into the lower MS Valley compared to GA and the
Carolinas, where the Slight Risk has been maintained with some
expansion.

...Northern Great Basin into the Northern Rockies/High Plains...
A closed mid/upper-level low over the Pacific Northwest and British
Columbia will pivot towards the northern Rockies through the period,
with a belt of enhanced mid-level flow overspreading the northern
Great Basin into the northern Rockies and adjacent High Plains in
MT. At the surface, mostly cloudy conditions are present over much
of western/central MT this morning. Even so, recent NAM/RAP forecast
soundings across this region show supercell profiles later this
afternoon and evening as mid/upper-level winds foster strong
deep-layer shear. Current expectations are for multiple supercells
to develop initially over the higher terrain and spread quickly
northeastward. While there is still some uncertainty regarding
boundary-layer destabilization, sufficient MUCAPE is forecast to
support supercell maintenance into the adjacent High Plains through
the evening. Large hail should be the main threat with this activity
(with some 2+ inches possible given the very favorable deep-layer
shear), but isolated severe gusts may also occur. The Slight Risk
has been adjusted/expanded a little eastward in MT based on latest
short-term guidance trends. High-based thunderstorms may also pose
an isolated threat for severe gusts across parts of the northern
Great Basin this afternoon.

...Northern/Central Plains into the Upper Midwest/Missouri Valley
and Ozarks...
Ongoing and likely elevated supercells with a threat for large hail
across parts of western ND are being aided by a subtle mid-level
shortwave trough cresting the upper ridge that is anchored over the
central CONUS. Favorable lapse rates aloft and modestly enhanced mid/upper-level southwesterly flow is likely supporting updraft organization/intensity with this ongoing activity. The airmass
downstream across central/eastern ND should gradually destabilize
through the afternoon, with a moist low-level airmass present to the
east of a weak surface low over eastern MT/southwest ND/northwest
SD. It remains unclear whether these ongoing supercells will be
maintained farther east across ND, but given the favorable airmass
and sufficient deep-layer shear present, have opted to add a
targeted Slight Risk for the large hail potential.

Additional convection is occurring farther south in SD, southwest
MN/northwest IA, and northeast NE in association with a mid-level
vorticity maximum evident on water vapor satellite imagery moving
eastward across SD/NE. There is a narrow corridor of greater
instability present across this region southward to the Ozarks,
generally along/near a weak surface front. Isolated hail may occur
with the stronger cores in the short term, but it remains unclear if
convection will be able to form into a southward-moving cluster
across eastern NE/western IA later this afternoon and evening. If
this does occur, then a greater threat for severe/damaging winds
would exist. Have deferred a possible upgrade to Slight Risk given
the uncertainty with how ongoing convection will evolve/impact the
developing warm sector, and due to the presence of the large-scale mid/upper-level ridge and generally modest flow aloft. A separate
area of high-based thunderstorms that should develop this afternoon
along/east of a surface lee trough across the central High Plains
could produce occasional hail and severe gusts, even as deep-layer
shear remains modest.

..Gleason/Thornton.. 09/06/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 6 20:02:58 2026

ACUS01 KWNS 062002
SWODY1
SPC AC 062000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Sep 06 2026

Valid 062000Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHEAST...MONTANA...AND THE MISSOURI VALLEY...

...SUMMARY...
Scattered damaging winds should occur across parts of the Southeast
this afternoon/early evening. Scattered large hail is forecast
across portions of Montana this afternoon and evening. A focused
corridor for damaging winds and severe hail is forecast across parts
of the Middle and Lower Missouri Valley. Isolated strong to severe thunderstorms may also occur today across parts of the northern
Great Basin, northern/central Plains, and the Ozarks.

...20Z Update...
A Slight Risk was added across parts of the Middle and Lower
Missouri Valley -- driven by 15-percent wind and hail probabilities.
Here, ample diurnal heating amid a very moist air mass is yielding a
corridor of strong surface-based buoyancy (around 4000 J/kg MLCAPE
per the latest HRRR SFCOA data). Large-scale ascent preceding a
convectively augmented midlevel impulse should promote an increase
in storm coverage in this north/south corridor through the
afternoon. The strong buoyancy and around 30 kt of effective shear
should promote a mix of organized clusters and possibly some
supercell structures -- capable of producing damaging wind gusts and
severe hail. See MCD #2253 for more details.

Farther north, the Slight Risk in ND was removed. The latest mode
evolution suggests a reduced hail threat compared to this morning.
However, a locally favorable corridor for damaging wind gusts may
develop into parts of eastern ND this afternoon/early evening.

Elsewhere, the previous forecast remains on track.

..Weinman.. 09/06/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Sep 06 2026/

...Southeast/Lower Mississippi Valley...
Recent visible satellite imagery shows mostly clear skies across
GA/SC late this morning, with surface temperatures already in the
mid/upper 80s to low 90s. A weak front is draped from northwest to
southeast from the southern Appalachians to the Atlantic Coast, with
generally low to mid 70s surface dewpoints present to its south.
Continued diurnal heating of this moist airmass will support the
development of moderate to strong instability (greater with
southward/westward extent into GA/AL and north FL). Compared to the
past couple of days, this region will be displaced from the stronger
mid-level west-northwesterly flow present across the
Mid-Atlantic/Northeast. Corresponding deep-layer shear is expected
to remain rather modest (less than 25 kt), with only loosely
organized updrafts forecast. Even with these kinematic limitations,
steepening low-level lapse rates through the afternoon may still
promote isolated to scattered damaging winds with clusters that
develop and spread south-southeastward through the early evening.
Isolated hail may also occur with the more robust cells that can
develop initially. The damaging wind threat should be more isolated
with westward extent into the lower MS Valley compared to GA and the
Carolinas, where the Slight Risk has been maintained with some
expansion.

...Northern Great Basin into the Northern Rockies/High Plains...
A closed mid/upper-level low over the Pacific Northwest and British
Columbia will pivot towards the northern Rockies through the period,
with a belt of enhanced mid-level flow overspreading the northern
Great Basin into the northern Rockies and adjacent High Plains in
MT. At the surface, mostly cloudy conditions are present over much
of western/central MT this morning. Even so, recent NAM/RAP forecast
soundings across this region show supercell profiles later this
afternoon and evening as mid/upper-level winds foster strong
deep-layer shear. Current expectations are for multiple supercells
to develop initially over the higher terrain and spread quickly
northeastward. While there is still some uncertainty regarding
boundary-layer destabilization, sufficient MUCAPE is forecast to
support supercell maintenance into the adjacent High Plains through
the evening. Large hail should be the main threat with this activity
(with some 2+ inches possible given the very favorable deep-layer
shear), but isolated severe gusts may also occur. The Slight Risk
has been adjusted/expanded a little eastward in MT based on latest
short-term guidance trends. High-based thunderstorms may also pose
an isolated threat for severe gusts across parts of the northern
Great Basin this afternoon.

...Northern/Central Plains into the Upper Midwest/Missouri Valley
and Ozarks...
Ongoing and likely elevated supercells with a threat for large hail
across parts of western ND are being aided by a subtle mid-level
shortwave trough cresting the upper ridge that is anchored over the
central CONUS. Favorable lapse rates aloft and modestly enhanced mid/upper-level southwesterly flow is likely supporting updraft organization/intensity with this ongoing activity. The airmass
downstream across central/eastern ND should gradually destabilize
through the afternoon, with a moist low-level airmass present to the
east of a weak surface low over eastern MT/southwest ND/northwest
SD. It remains unclear whether these ongoing supercells will be
maintained farther east across ND, but given the favorable airmass
and sufficient deep-layer shear present, have opted to add a
targeted Slight Risk for the large hail potential.

Additional convection is occurring farther south in SD, southwest
MN/northwest IA, and northeast NE in association with a mid-level
vorticity maximum evident on water vapor satellite imagery moving
eastward across SD/NE. There is a narrow corridor of greater
instability present across this region southward to the Ozarks,
generally along/near a weak surface front. Isolated hail may occur
with the stronger cores in the short term, but it remains unclear if
convection will be able to form into a southward-moving cluster
across eastern NE/western IA later this afternoon and evening. If
this does occur, then a greater threat for severe/damaging winds
would exist. Have deferred a possible upgrade to Slight Risk given
the uncertainty with how ongoing convection will evolve/impact the
developing warm sector, and due to the presence of the large-scale mid/upper-level ridge and generally modest flow aloft. A separate
area of high-based thunderstorms that should develop this afternoon
along/east of a surface lee trough across the central High Plains
could produce occasional hail and severe gusts, even as deep-layer
shear remains modest.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 7 00:42:32 2026

ACUS01 KWNS 070042
SWODY1
SPC AC 070040

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 PM CDT Sun Sep 06 2026

Valid 070100Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
WESTERN AND CENTRAL MONTANA AND OVER A SMALL PART OF THE LOWER
MISSOURI VALLEY...

...SUMMARY...
Widely scattered large hail occurrences with hailstones up to two
inches are expected over portions of western and central Montana
this evening into tonight. More sporadic occurrences of large hail
and severe wind gusts appear possible over the northern and central
High Plains, and across parts of the lower Missouri Valley.

...Northern Rockies into the northern Plains...

Separate vorticity lobes and associated wind maxima will progress
into the northern Rockies and northern High Plains tonight with a
resultant zone of height falls/forcing for ascent overspreading the
region. In the lower levels, a surface cyclone will be maintained
over southeast MT while a nocturnal jet develops over the northern
and central High Plains.

Thunderstorms currently intensifying over western MT are expected to
increase in coverage and intensity while spreading into
north-central MT ahead of the western vorticity lobe rounding the
base of the Pacific Northwest upper low. While the boundary layer is
somewhat cool/stable, the presence of steep mid-level lapse rates,
MUCAPE up to 1000-1500 J/kg, and 40-45 kt of effective bulk shear
will be supportive of supercells with the primary hazard being large
hail up to two inches.

Farther east, isolated to widely scattered storms have developed
along and ahead of a lee trough and the MT surface low from western
ND into northeast CO within a steep lapse rate and moderately
unstable environment (see the 00Z UNR and LBF soundings). Veering
winds with height with up to 35-40 kt of deep-layer shear are
sufficient to support an observed supercell storm mode with the
primary hazards being large hail potentially in excess of two inches
and locally severe wind gusts. A tornado was recently reported with
a slow-moving supercell over McKenzie County, ND. However, sizable temperature-dewpoint spreads within the inflow air mass, and the
tendency for increasing convective inhibition in the coming hours
are likely to limit a continuing tornado threat despite increasing
low-level shear.

Storm coverage is expected to remain limited through the remainder
of the evening with a potential increase later tonight with the
arrival of the eastern vorticity lobe and strengthening low-level
jet. As such, the threat for sporadic large hail and severe wind
gust occurrences may linger into the overnight hours from eastern MT
into the western parts of the Dakotas and NE.

For additional information, see recently issued mesoscale discussion
#2259.

...Lower Missouri Valley...

Widely scattered strong to severe storms are ongoing this evening
over parts of southeast NE, northeast KS, and northwest MO with
activity focused along outflow boundaries and a synoptic front in
the area. The inflow air mass remains hot and relatively moist as of
00Z with observed soundings indicating steep low-level lapse rates
with MLCAPE up to 1500-3000 J/kg. The 00Z TOP sounding sampled
around 30 kt of deep-layer shear, which will remain supportive of
episodic supercell structures for the next couple of hours with an
associated risk for large hail and locally damaging wind gusts.

For additional information, see recently issued mesoscale discussion
#2258.

..Mead.. 09/07/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 7 05:58:18 2026

ACUS01 KWNS 070556
SWODY1
SPC AC 070555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Mon Sep 07 2026

Valid 071200Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHWEST
INTO CENTRAL NORTH DAKOTA AND SOUTHEAST SOUTH DAKOTA INTO NORTHEAST
NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly large hail are
expected over portions of northwest and central North Dakota and
southeast South Dakota into northeast Nebraska Monday afternoon into
evening. A tornado or two is possible in southeast South Dakota. A
broader area of isolated large hail and damaging wind potential
exists over the northern and central Plains into upper Mississippi
Valley. Locally damaging wind gusts appear possible over the central
Gulf Coast states Monday afternoon and evening.

...Synopsis...

A vigorous short-wave trough will pivot from the northern Rockies
through the northern High Plains with an associated strengthening of
the mid/upper-level wind field forecast across the northern Plains
into the upper MS Valley. A low-level jet (LLJ) will also be
sustained over the northern and central Plains into upper MS Valley
ahead of a surface cold front advancing through the northern Plains
and central High Plains.

...Northern and central Plains into the upper Mississippi Valley...

Clusters of mainly elevated thunderstorms may be ongoing at 12Z
Monday from eastern MT into the Dakotas within a zone of forcing for
ascent preceding a lead, mid-level disturbance and coincident with
the exit region of the LLJ. The presence of steep mid-level lapse
rates, MUCAPE of 1000-1500 J/kg, and 35-45 kt of effective bulk
shear will be supportive of some storm organization with an
associated risk for isolated large hail occurrences through the
morning hours as that convective regime shifts east across the
Dakotas.

On the periphery of more persistent cloudiness associated with the
morning storms, stronger insolation coupled with dewpoints in the
upper 60s to low 70s F and modestly steep mid-level lapse rates are
expected to yield a moderately unstable air mass by mid to late
afternoon with MLCAPE up to 1500-2500+ J/kg and a weakening cap.
Surface-based thunderstorm development will become increasingly
likely at that time, aided by increasing height falls attending the
primary short-wave trough.

The 00Z models indicate one potentially favored location for storm
development over portions of south-central and southeast SD into
northeast CO, from the vicinity of a secondary surface low southwest
along a pre-frontal trough. RAP-based hodographs over southeast SD
indicate considerable veering through the lowest 1-2 km AGL with
effective SRH of 200-300 m2/s2 and effective bulk shear magnitudes
of 40-45 kt, owing to the proximity of the LLJ. Accompanying
thermodynamic profiles suggest modest low-level lapse rates with
some residual capping. However, given surface-based storm initiation
and sustenance, supercells would be likely with an associated large
hail and tornado threat.

A hotter and more well-mixed boundary layer is expected with
southwestward extent ahead of the pre-frontal trough where
high-based storms capable of severe wind gusts and hail appear
possible.

Surface-based storms also appear possible ahead of an occluding
surface low and trailing cold front from northwest into central ND.
While the boundary layer may remain relatively cool from the
early-day storms, cooling mid-level temperatures will effectively
steepen lapse rates, yielding sufficient instability amidst 40-50 kt
of deep-layer layer. As such, supercells appear possible with an
attendant risk for large hail.

...Central Gulf Coast...

A hot and very moist air mass is forecast Monday afternoon ahead of
a weak front pushing into the region from the north with MLCAPE
increasing to 2500-3500 J/kg. Forcing for ascent will remain weak as
will vertical shear; however, the degree of instability and high
moisture content will be supportive of intense pulse storms capable
of damaging wet microbursts from mid-afternoon into evening.

..Mead/Chalmers.. 09/07/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 7 12:46:08 2026

ACUS01 KWNS 071245
SWODY1
SPC AC 071244

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0744 AM CDT Mon Sep 07 2026

Valid 071300Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
NORTH DAKOTA AND SOUTHEAST SOUTH DAKOTA INTO NORTHEAST NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly large hail are
expected over portions of North Dakota as well as southeast South
Dakota into northeast Nebraska this afternoon into evening. A
broader area of isolated large hail and damaging wind potential
exists over the northern and central Plains into upper Mississippi
Valley. Locally damaging wind gusts appear possible over the central
Gulf Coast states Monday afternoon and evening.

...Northern/Central Plains into the Upper Mississippi Valley...
Early-morning satellite imagery depicts a deep upper trough over the
western CONUS. A trio of notable shortwave troughs are embedded
within this larger troughing, with the lead wave currently
progressing through eastern MT. Expectation is for this lead wave to
continue northeastward into the southern Canadian Prairie Provinces.
Surface low attendant to this lead shortwave is currently over
east-central MT. This low is also forecast to progress northeastward
just ahead of its parent shortwave for much of the day, before then
occluding over southern Saskatchewan this evening.

Showers and thunderstorms are currently ongoing from central MT into
western ND in the vicinity of this surface low, supported by a
combination of warm advection around the low and large-scale ascent
attendant to the shortwave trough. Warm-air advection is also
supporting additional thunderstorms from the NE Panhandle into
central SD. All of this activity is expected to gradually to shift northeastward this morning in tandem with the progression of the
shortwave and its stronger low/mid-level southerly flow. Steep
mid-level lapse rates, MUCAPE of 1000-1500 J/kg, and 35-45 kt of
effective bulk shear could support occasional storm organization
with an associated risk for isolated large hail.

Renewed thunderstorm development is anticipated this afternoon in
several areas in the wake of the morning storms. One area is along a dryline-like surface trough that is forecast to extend from the
occluding low over southern Saskatchewan to another low over western
SD. Strong low-level convergence is likely along this boundary, with
dewpoints remaining in the mid to upper 60s just east of the
boundary. Some convective inhibition may linger, and overall storm
coverage will likely remain isolated to widely scattered as a
result. However, any storms that develop should become supercells
capable of all severe hazards, including very large hail and a brief
tornado.

Another area is over portions of south-central and southeast SD into
northeast CO, from the vicinity of the secondary surface low of
western SD southwest along a pre-frontal trough. Some limited
convective inhibition may remain over this region as well, likely
keeping the overall storm coverage isolated to widely scattered.
Even so, kinematic profiles do support the potential for supercells
with any persistent deep convective, particularly over southeast SD.
Here, the proximity to the low-level jet results in considerable
veering through the lowest 1-2 km AGL, with effective SRH of 200-300
m2/s2 and effective bulk shear magnitudes of 40-45 kt. Primary
severe risk with any supercells is large to very large hail,
although the low-level veering will support some tornado risk as
well.

...Central Gulf Coast...
A hot and very moist air mass is forecast this afternoon ahead of a
weak front pushing into the region from the north with MLCAPE
increasing to 2500-3500 J/kg. Forcing for ascent and vertical shear
will remain weak; however, the degree of instability and high
moisture content will be supportive of intense pulse storms capable
of damaging wet microbursts from mid-afternoon into evening.

..Mosier/Lyons.. 09/07/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 7 16:14:06 2026

ACUS01 KWNS 071613
SWODY1
SPC AC 071612

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1112 AM CDT Mon Sep 07 2026

Valid 071630Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PARTS OF CENTRAL NORTH DAKOTA AND SOUTHEAST SOUTH
DAKOTA...

...SUMMARY...
Widely scattered severe storms capable of mainly large hail are
expected over portions of North Dakota as well as southeast South
Dakota into northeast Nebraska this afternoon into evening. Isolated
damaging wind potential will exist over the northern and central
Plains into upper Mississippi Valley. Locally damaging wind gusts
appear possible this afternoon over the central Gulf Coast states.

...ND...
A fast-moving shortwave trough currently over WY/MT will track
northeastward into the Dakotas this afternoon. Strong
heating/mixing in southwest ND will lead to a sharpening dryline
across central ND by mid/late afternoon. This will be the likely
focus for thunderstorm development after 22z. Forecast soundings in
the warm-sector east of the dryline suggest sufficient low-level and
deep-layer shear for supercell storm-modes. Large hail and perhaps a
tornado or two are possible in the most intense storms. This
activity will spread eastward into northeast ND this evening before
weakening.

...CO/KS/NE/SD...
A weak surface boundary is present today from northeast CO into
central NE. Scattered afternoon thunderstorms will form over the
mountains of central CO, with development spreading eastward along
the boundary through the afternoon. Strong heating and a deeply
mixed boundary-layer will promote intense downdrafts in the
strongest cores. By early evening, activity may spread into
southeast SD where greater low-level moisture and CAPE will pose a
risk of a few more intense storms capable of hail or even a tornado.
Recent model solutions have been backing off on this SD scenario,
but will maintain the ongoing SLGT for now.

...LA/MS/AL...
Hot and humid conditions will prevail over the central Gulf coast
region today, with full sunshine and dewpoints in the low-mid 70s.
Steering flow is weak, but high CAPE and ample moisture suggest a
risk of occasional intense downdrafts in the strongest storms.

..Hart/Thornton.. 09/07/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 7 20:01:14 2026

ACUS01 KWNS 072000
SWODY1
SPC AC 071959

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Mon Sep 07 2026

Valid 072000Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL NORTH DAKOTA AND SOUTHEAST SOUTH DAKOTA...

...SUMMARY...
Widely scattered severe storms capable of mainly large hail are
expected over portions of North Dakota as well as southeast South
Dakota into northeast Nebraska this afternoon into evening. Isolated
damaging wind potential will exist over the northern and central
Plains into the upper Mississippi Valley. Locally damaging wind
gusts remain possible this afternoon over the central Gulf Coast
states.

...20Z Update...
The MRGL Risk/5-percent wind area was expanded slightly
west-southwestward in parts of eastern MT. Here, a small
north/south-oriented line segment is tracking eastward into an
increasingly warm PBL. This activity will continue to pose a risk of
a few severe wind gusts this afternoon. See MCD #2264 for more
details. Elsewhere, very minimal changes were made with this update.

..Weinman.. 09/07/2026

.PREV DISCUSSION... /ISSUED 1112 AM CDT Mon Sep 07 2026/

...ND...
A fast-moving shortwave trough currently over WY/MT will track
northeastward into the Dakotas this afternoon. Strong
heating/mixing in southwest ND will lead to a sharpening dryline
across central ND by mid/late afternoon. This will be the likely
focus for thunderstorm development after 22z. Forecast soundings in
the warm-sector east of the dryline suggest sufficient low-level and
deep-layer shear for supercell storm-modes. Large hail and perhaps a
tornado or two are possible in the most intense storms. This
activity will spread eastward into northeast ND this evening before
weakening.

...CO/KS/NE/SD...
A weak surface boundary is present today from northeast CO into
central NE. Scattered afternoon thunderstorms will form over the
mountains of central CO, with development spreading eastward along
the boundary through the afternoon. Strong heating and a deeply
mixed boundary-layer will promote intense downdrafts in the
strongest cores. By early evening, activity may spread into
southeast SD where greater low-level moisture and CAPE will pose a
risk of a few more intense storms capable of hail or even a tornado.
Recent model solutions have been backing off on this SD scenario,
but will maintain the ongoing SLGT for now.

...LA/MS/AL...
Hot and humid conditions will prevail over the central Gulf coast
region today, with full sunshine and dewpoints in the low-mid 70s.
Steering flow is weak, but high CAPE and ample moisture suggest a
risk of occasional intense downdrafts in the strongest storms.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 01:00:18 2026

ACUS01 KWNS 080059
SWODY1
SPC AC 080058

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 PM CDT Mon Sep 07 2026

Valid 080100Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER CENTRAL NORTH
DAKOTA AND SOUTHEAST SOUTH DAKOTA...

...SUMMARY...
The threat for widely scattered severe storms capable of large hail
and perhaps a tornado or two will continue over central North Dakota
and southeast South Dakota into tonight. More isolated occurrences
of large hail and severe wind gusts remain possible this evening
over the central High Plains.

...Northern Plains...

Two separate severe thunderstorm regimes have evolved late this
afternoon into evening. The first is over northwest into central ND,
where widely scattered storms --including a supercell-- are ongoing
ahead of a cold front pushing through western ND. The 00Z BIS
sounding showed modestly steep low-level lapse rates and a moist
boundary layer with MLCAPE CAPE of around 3000 J/kg. The
corresponding wind profile was quite supportive of updraft rotation
with effective SRH of around 300 m2/s2 and 60 kt of effective bulk
shear, suggesting the supercell north of BIS will remain capable of
large hail and a tornado or two for the next hour or two.
Thereafter, increasing convective inhibition may result in the
gradual weakening of the storms with a decreasing severe weather
threat.

For additional near-term guidance on that regime, see recently
issued MCD #2268.

The second thunderstorm regime is evolving across portions of
northeast NE into southeast SD, near the intersection of a
differential heating zone/outflow boundary and a pre-frontal trough.
The boundary layer to the north of the baroclinic zone over
southeast SD is slightly cooler with some convective inhibition
noted in latest objective analysis fields. However, the presence of
MLCAPE up to 2000-3000 J/kg, which coincides with 35-40 kt of
deep-layer shear is supportive of supercells with the primary hazard
being large hail, potentially in excess of two inches. The nocturnal strengthening of the low-level jet is resulting in enlarging
low-level hodographs with effective SRH of 300-400+ m2/s2, per
objective analysis. A tornado recently occurred with the ongoing
storms near the NE-SD border with an additional tornado or two
remaining possible this evening before convective inhibition
increases further.

..Mead.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 05:40:22 2026

ACUS01 KWNS 080539
SWODY1
SPC AC 080538

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Tue Sep 08 2026

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
IOWA AND EASTERN NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly severe wind gusts
appear possible across portions of Iowa and eastern Nebraska Tuesday
afternoon and evening. More sporadic occurrences of severe winds and
large hail may occur from portions of the upper Midwest into the
central Plains.

...Synopsis...

An intense upper low moving into southern SK late this evening will
continue northeast through central MB into northern ON ahead of a
secondary short-wave trough tracking from the northern Rockies into
the northern Plains. A belt of enhanced mid/upper-level winds will
be maintained between those features from the northern High Plains
into the upper Great Lakes. At the surface, a cold front will
advance through the eastern Dakotas and upper MS Valley with the
trailing extension of the boundary moving more slowly southeast
through the mid-MO Valley and central High Plains.

...Central Plains into the upper Midwest...

Clusters of thunderstorms are likely to be ongoing at 12Z Tuesday
from portions of the mid-MO Valley into the upper Midwest within a
zone of warm advection and moisture transport along a nocturnal
low-level jet (LLJ). Showers and storms may linger through the
morning across parts of WI and the U.P. of MI, limiting the degree
of air mass destabilization and associated severe weather risk
during the afternoon. Farther to the southwest from IA through
eastern and southern NE into northern KS, stronger daytime heating
on the southern fringe of lingering mid/high-level cloudiness will
contribute to a well-mixed boundary layer, featuring steep low-level
lapse rates. When combined with boundary-layer dewpoints in the 60s
to low/mid 70s F, the air mass is expected to become moderately to
strongly unstable by late afternoon with MLCAPE of 2000-3000 J/kg.

In the absence of appreciable height falls/large-scale forcing for
ascent, convergence along the front and any preceding confluence
zones/outflow boundaries is expected to foster a gradual increase in
storm coverage and intensity by mid to late afternoon amidst the
destabilizing air mass. The strongest deep-layer shear is expected
to be displaced to the north of the effective warm sector with
around 30-35 kt forecast along the frontal zone. A largely parallel shear-vector orientation with the front suggests that initial storms
should grow upscale into line segments or a broken band with an
associated risk for severe wind gusts from mid afternoon through
evening. Isolated occurrences of marginally severe hail are
possible; however, poor mid-level lapse are expected to limit the
overall threat. The 00Z models do indicate some LLJ enhancement over
central IA by late afternoon into evening, resulting in a corridor
of stronger low-level shear. While a brief tornado or two are
possible, a more robust threat is expected to be limited by largely outflow-dominant storms.

..Mead/Chalmers.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 12:33:14 2026

ACUS01 KWNS 081233
SWODY1
SPC AC 081231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Tue Sep 08 2026

Valid 081300Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
CENTRAL IOWA AND FAR EASTERN NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly severe wind gusts
appear possible across portions of Iowa and eastern Nebraska Tuesday
afternoon and evening. More sporadic occurrences of severe winds and
large hail may occur from portions of the upper Midwest into the
central Plains.

...Central Plains into the upper Midwest...
An extensive low-level jet is currently in place from the southern
High Plains through the Upper Midwest. Warm-air advection associated
with this feature is contributing to showers and thunderstorms from
eastern NE through WI and into western Upper MI. This activity is
forecast to gradually shift northeastward this morning while the
embedded storms also gradually diminish in strength. These showers
and thunderstorms, and associated warm low to mid-level
temperatures, are expected to limit destabilization across much of
WI and Upper MI.

Some moderate buoyancy is possible by the early afternoon across MN,
just ahead of a cold front pushing eastward into the region.
Lingering convective inhibition will likely limit convective
initiation, and considerable uncertainty exists regarding
thunderstorm coverage. This uncertainty precludes introducing any
severe probabilities, but the combination of moderate buoyancy and
strong deep-layer shear over the region would support some severe
potential with any updrafts that persist and mature.

Farther south and west (i.e. from IA through eastern/southern NE
into northern KS), stronger daytime heating will contribute to a
well-mixed boundary layer, characterized by steep low-level lapse
rates and dewpoints in the 60s to low/mid 70s F. This air mass is
expected to become moderately to strongly unstable by late afternoon
with MLCAPE of 2000-3000 J/kg. Thunderstorm development is expected
as the southeastward-progressing cold front interacts with this
destabilized and buoyant airmass. The stronger vertical shear will
be displaced north/northeast of the greater buoyancy, but 30 to 35
kt of effective bulk shear is still sufficient for some storm
organization. A largely parallel shear-vector orientation with the
front suggests that initial storms should grow upscale quickly into
line segments or broken bands, with some tendency for undercutting
as well. Even so, a few damaging wind gusts will be possible from
mid afternoon through evening. The low-level jet will increase again
from western KS through central IA this evening resulting in a
corridor of stronger low-level shear. This low-level shear will
support a low-probability tornado risk, but a more robust threat is
expected to be limited by largely outflow-dominant and/or elevated
storms.

...CO Plains into western KS...
Thunderstorm development appears likely across the higher terrain of
central CO as the mid-level flow veers more westerly during the late
afternoon. Moist post-frontal northerly low-level flow is expected
across the CO Plains and western KS this evening, which could result
in enough buoyancy to maintain modest intensity as the central CO
storms progress eastward. High-based storm character and prevailing
steep low-level lapse rates may result in a few stronger gusts as
this cluster moves eastward into western KS.

..Mosier/Lyons.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 16:17:44 2026

ACUS01 KWNS 081617
SWODY1
SPC AC 081615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1115 AM CDT Tue Sep 08 2026

Valid 081630Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST NEBRASKA ACROSS PARTS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa and eastern Nebraska this afternoon
and evening.

...NE/IA...
A broad upper ridge remains over much of the central/southern US,
with moderately strong westerly flow over the northern tier of
states. A baroclinic zone extends across southern NE into central
IA. This feature will be sharpened by differential heating through
the day, and will be the focus for afternoon and evening
thunderstorm development. The strongest cells will be near a 20-30
knot southwesterly low-level jet where warm advection and lift will
aid in convective initiation. Sufficient deep-layer shear will
promote supercell and eventual bowing structures, with damaging
winds be the main concern. Most CAM solutions suggest the majority
of convection will be just north of the surface boundary, which may
limit the overall severe threat. Also, weak mid-level lapse rates
and warm temperatures aloft will tend to diminish the hail risk.

...CO/KS...
Farther southwest, hot surface conditions will result in a deeply
mixed boundary layer. Scattered high-based showers and
thunderstorms are expected to form from eastern CO into
western/central KS, with gusty and occasionally damaging wind gusts
possible.

..Hart/Guyer.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 19:49:14 2026

ACUS01 KWNS 081949
SWODY1
SPC AC 081947

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Tue Sep 08 2026

Valid 082000Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST NEBRASKA ACROSS PARTS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa and eastern Nebraska this afternoon
and evening.

...20Z Update...
The ongoing forecast remains on track and no changes are needed.

..Wendt.. 09/08/2026

.PREV DISCUSSION... /ISSUED 1115 AM CDT Tue Sep 08 2026/

...NE/IA...
A broad upper ridge remains over much of the central/southern US,
with moderately strong westerly flow over the northern tier of
states. A baroclinic zone extends across southern NE into central
IA. This feature will be sharpened by differential heating through
the day, and will be the focus for afternoon and evening
thunderstorm development. The strongest cells will be near a 20-30
knot southwesterly low-level jet where warm advection and lift will
aid in convective initiation. Sufficient deep-layer shear will
promote supercell and eventual bowing structures, with damaging
winds be the main concern. Most CAM solutions suggest the majority
of convection will be just north of the surface boundary, which may
limit the overall severe threat. Also, weak mid-level lapse rates
and warm temperatures aloft will tend to diminish the hail risk.

...CO/KS...
Farther southwest, hot surface conditions will result in a deeply
mixed boundary layer. Scattered high-based showers and
thunderstorms are expected to form from eastern CO into
western/central KS, with gusty and occasionally damaging wind gusts
possible.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 00:38:18 2026

ACUS01 KWNS 090038
SWODY1
SPC AC 090036

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0736 PM CDT Tue Sep 08 2026

Valid 090100Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS PORTIONS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa this evening.

...Discussion...
Widely scattered thunderstorm activity continues across the surface
boundary extending from portions of central/southern Iowa into
southern Nebraska and northern/western Kansas. A more organized
cluster is ongoing across portions of south-central Iowa. This
cluster will continue to pose a wind threat for the next couple of
hours before eventually moving southeast into less favorable air
across southeastern Iowa/western Illinois. Additional convection
will evolve overnight with the increasing low-level jet across
central Kansas into southeastern Nebraska and southern Iowa. This
will pose at least some potential for small hail and strong to
severe wind.

Across Colorado, scattered convection is ongoing near the foothills
of the Front Range. Time lagged HRRR/RRFS guidance continues to
suggest that this evolves into a cluster with potential for strong
to severe wind to continue downstream this evening. Though moisture
is limited, very warm surface temperatures and steep low to
mid-level lapse rates are supporting at least marginally unstable
conditions downstream.

..Thornton.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 05:43:46 2026

ACUS01 KWNS 090543
SWODY1
SPC AC 090541

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 AM CDT Wed Sep 09 2026

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO
INTO WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley on Wednesday. A more
organized severe weather threat is expected from eastern Ohio to
western New York.

...Synopsis...
A belt of enhanced mid-level flow will move through the broad
upper-level trough across Ontario, overspreading the Great Lakes
into Upstate New York and Quebec. A cold front will extend from a
deep surface low across northern Ontario south through the Upper
Midwest and into the central High Plains. Isolated to widely
scattered thunderstorm activity is expected near the surface trough
across the Ohio Valley into the Northeast and along the front from
the Midwest to the central High Plains.

...Eastern Ohio into western New York...
Across the eastern Ohio Valley into portions of the Northeast,
strengthening mid-level flow will overspread the region with
thunderstorms developing along the cold front and pre-frontal
surface trough. Upper 60s to 70s dew points and filtered daytime
heating will yield moderate instability amid ample deep layer shear
for organization. Mode will likely be a mix of multi-cell clusters
and transient supercells, with potential for damaging wind.
Generally weak lapse rate profiles and quick mode transition to
clusters/linear segments should limit hail and tornado potential.
Nonetheless, as the low-level jet increases into the afternoon and
clockwise curvature increases in hodographs a tornado may be
possible.

...Ohio Valley to the Midwest and the central Plains...
Morning convection will be likely across much of the
Midwest/Mid-Missouri Valley into the northwestern Ohio Valley.
Remnant shower activity/cloud cover will likely limit severe
potential with northern extent. Nonetheless, isolated to widely
scattered thunderstorm activity is expected to develop by the
afternoon along the front and remnant outflow from the eastern Ohio
Valley through portions of the Midwest and into the central Plains.
Flow will be fairly weak across the central Plains, with generally a
marginal damaging wind threat with multi-cell clusters as daytime
heating steepens low-level lapse rates amid deeply mixed profiles.
Slightly better flow aloft may favor a more focused cluster across
the Mid-Mississippi Valley into western Kentucky/Tennessee.

..Thornton/Chalmers.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 12:43:48 2026

ACUS01 KWNS 091243
SWODY1
SPC AC 091241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Wed Sep 09 2026

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL OHIO
FROM WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today. A more organized
severe weather threat is expected from eastern Ohio to western New
York.

...Synopsis...
Early-morning satellite imagery show broad upper troughing from the
Pacific Northwest/British Columbia through the Upper Great Lakes and
Ontario. Several shortwave troughs are embedded within this larger
upper troughing, including one moving into northern MN and another
farther north across far northwestern Ontario. A belt of moderate to
strong mid-level westerly/southwesterly flow extends between the
base of these two waves. Expectation is the southern wave to move
quickly eastward through the Upper Great Lakes and Ontario,
accompanied by mid-level jet max.

Surface analysis places a occluded low over far northwestern
Ontario, with a cold front extending southward into western Upper MI
and then back southwestward through central NE. An outflow-augmented pre-frontal trough precedes this front, extending from a low in
southwest Lower MI to another low over northeast KS to another over
far southwest KS/far southeast CO. Both the cold front and
pre-frontal trough are expected to progress modestly
southward/southeastward today. Two corridors of relatively higher
thunderstorm coverage are anticipated this afternoon/evening, one
from eastern OH into western PA/western NY and the other farther
southwest from the Lower MO Valley into the TX/OK Panhandles.

...Central Ohio into western New York...
Moist low-levels are already in place from the OH Valley into
western PA and NY, with recent surface analysis sampling upper 60s
dewpoints in central OH decreasing to the low/mid 60s across western
PA and western NY. This moist airmass is expected to destabilize
amid modest low-level moisture advection and filtered insolation,
ahead of a convectively augmented vorticity maximum. With the cold
front still well to the northwest, this vorticity maximum will be
the primary impetus for thunderstorm development, augmenting the
weak low-level confluence along the weak pre-frontal trough. A
predominately linear/clustered storm mode is anticipated, but
strengthening mid-level flow will support effective bulk shear from
30 to 40 kt, which could support some more persist/organized line
segments. Damaging gusts are the primary risk with any of these more
organized segments. Low-level hodographs do show some notable
curative, particularly from western PA into western NY after 00Z,
amid a strengthening low-level jet. As such, there is a
low-probability tornado risk is these areas.

...Lower OH and MO Valleys into the TX/OK Panhandles...
Thunderstorm coverage is gradually expected to increase across the
region this afternoon and evening, beginning near a surface low move
across the Lower MO Valley before expanding back southwestward along
the southward-progressing front. The stronger vertical shear will be
displace north of the front, and a largely disorganized,
outflow-dominant storm mode is anticipated. Slightly better flow
aloft may favor a more focused cluster across the Mid-Mississippi
Valley into western Kentucky/Tennessee. Steep low-level lapse rates
and high cloud bases could support strong gusts from the Lower MO
Valley into the TX/OK Panhandles.

...Southern AZ...
Afternoon thunderstorms are expected over the higher terrain near
the southern AZ/NM border. There is some potential this activity
progresses westward into the lower elevations of southern AZ.
However, upper ridging will be centered over this region and
vertical shear will be weak, resulting in slow storm motion and
disorganized, outflow-dominant structures. A few strong gusts could
result from any more persistent updrafts.

..Mosier/Lyons.. 09/09/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Sep 9 16:29:34 2026

ACUS01 KWNS 091629
SWODY1
SPC AC 091627

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Wed Sep 09 2026

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM CENTRAL OHIO INTO NORTHWEST PENNSYLVANIA AND WESTERN
NEW YORK....

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today.

...OH/PA/NY...
A fast-moving shortwave trough now over WI/IL will track eastward
today across the Great Lakes region. At the surface, the primary
baroclinic currently extends from Lake Erie into OH/IN and will move
eastward and be the focus for scattered afternoon thunderstorms.
Strong heating and dewpoints in the 70s across much of OH and
western PA will result in moderate CAPE values and steep low-level
lapse rates. Sufficient deep-layer shear will promote organized
storms with some bowing structures expected, capable of locally
damaging wind gusts. This activity will spread into western
NY/northwest PA by early evening before weakening.

...IN/IL/MO...
The storms that form over OH will zipper southwestward along the
boundary into a pocket of ample CAPE/moisture over parts of southern
IN/IL into southern MO. Winds aloft in this area will be weaker,
with less overall organization of storms. Nevertheless, a few
storms may occasionally produce damaging wind gusts.

...TX/OK/KS...
Widely scattered slow-moving afternoon thunderstorms will pose a
risk of gusty/damaging winds in a hot/humid surface air mass.

..Hart/Guyer.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 20:04:48 2026

ACUS01 KWNS 092004
SWODY1
SPC AC 092002

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0302 PM CDT Wed Sep 09 2026

Valid 092000Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM CENTRAL OHIO INTO NORTHWEST PENNSYLVANIA AND WESTERN
NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today.

...20Z Update...
Minor changes were made to the general thunderstorms forecast based
on observations and recent guidance. Severe probabilities remain
unchanged, however. See the previous discussion for additional
information.

..Wendt.. 09/09/2026

.PREV DISCUSSION... /ISSUED 1127 AM CDT Wed Sep 09 2026/

...OH/PA/NY...
A fast-moving shortwave trough now over WI/IL will track eastward
today across the Great Lakes region. At the surface, the primary
baroclinic currently extends from Lake Erie into OH/IN and will move
eastward and be the focus for scattered afternoon thunderstorms.
Strong heating and dewpoints in the 70s across much of OH and
western PA will result in moderate CAPE values and steep low-level
lapse rates. Sufficient deep-layer shear will promote organized
storms with some bowing structures expected, capable of locally
damaging wind gusts. This activity will spread into western
NY/northwest PA by early evening before weakening.

...IN/IL/MO...
The storms that form over OH will zipper southwestward along the
boundary into a pocket of ample CAPE/moisture over parts of southern
IN/IL into southern MO. Winds aloft in this area will be weaker,
with less overall organization of storms. Nevertheless, a few
storms may occasionally produce damaging wind gusts.

...TX/OK/KS...
Widely scattered slow-moving afternoon thunderstorms will pose a
risk of gusty/damaging winds in a hot/humid surface air mass.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 00:42:24 2026

ACUS01 KWNS 100042
SWODY1
SPC AC 100040

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 PM CDT Wed Sep 09 2026

Valid 100100Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS A PORTION OF THE
UPPER OHIO VALLEY...

...SUMMARY...
Isolated severe storms capable of mainly damaging wind gusts will
remain possible through late evening from the upper Ohio Valley into
the southern Plains.

...Upper Ohio Valley/Lower Great Lakes...

Scattered thunderstorms are ongoing this evening along and ahead of
a cold front from north-central PA into central OH within a moist
air mass with the 00Z Pittsburgh sounding indicating MLCAPE of
around 1000 J/kg. Moreover, the corresponding wind profile exhibited
relatively strong low-level and deep-layer shear with effective SRH
of around 250 m2/s2 and effective bulk shear of around 40 kt. So,
while lapse rates and resultant instability are expected to weaken
with the loss of daytime heating, the kinematic environment will
remain supportive of transient supercell and bowing structures
capable of locally damaging wind gusts and perhaps a tornado for the
next couple of hours.

...Southern Plains into the Ozarks...

A thunderstorm complex ongoing southeast of Kansas City this evening
is located to the north of the synoptic front that stretches from
central MO through far southeast KS and northwest OK into the TX
Panhandle. Some cold pool organization is present per KEAX base
velocity data, with recent reports of wind damage and wind gusts up
to 59 mph. The air mass ahead of the storms has been slightly
modified by convective outflow but still remains sufficiently
buoyant to sustain the ongoing storms with a continued risk for
isolated severe wind gusts through the remainder of the evening.

Over the southern Plains, widely scattered thunderstorms continue
this evening along and in the immediate wake of the front. The air
mass ahead of the front remains hot with a deep, well-mixed boundary
layer, which will remain supportive of locally severe wind gusts for
the next hour or two.

..Mead.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 05:38:28 2026

ACUS01 KWNS 100538
SWODY1
SPC AC 100536

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1236 AM CDT Thu Sep 10 2026

Valid 101200Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE SOUTHERN MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast Thursday afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles Thursday afternoon and
evening.

...Synopsis...

A short-wave trough initially over the upper MS and mid MO Valleys
Thursday morning will continue east into the Great Lakes and OH
Valley with a preceding belt of enhanced mid-level flow extending
into the Mid-Atlantic. Elsewhere, a vorticity maximum (possible MCV)
is forecast to progress from western KS into the Ozark Plateau by
Thursday night. At the surface, a cool front is expected to advance
through the Mid-Atlantic during the forecast period with the western
extension of the boundary settling more slowly south through the OH
Valley, Ozark Plateau, and southern Plains. The location of the
surface front is likely to be modulated by clusters of thunderstorms
that are expected to be ongoing Thursday morning from portions of
the OH Valley into the southern Plains.

...Southern Plains to the southern Mid-Atlantic coast...

To the south of residual cloudiness and lingering showers and
thunderstorms, a hot air mass is expected to develop by afternoon
with temperatures well into the 90s to around 100 F over the
southern Plains into the lower MS Valley, and upper 80s to mid 90s
from the TN Valley to Mid-Atlantic. While mid-level lapse rates will
remain generally less than 7 C/km, the daytime heating coupled with
dewpoints in the 60s to low/mid 70s will yield a moderately unstable
air mass by afternoon with MLCAPE ranging from 1500-2500+ J/kg.

The 00Z models indicate a gradual increase in thunderstorm coverage
and intensity through the afternoon, aided by forcing for ascent
associated with the mid-level disturbances mentioned in the
synopsis, as well as convergence along the synoptic front and any
existing outflow boundaries. The strongest mid/upper-level wind
field and resultant vertical shear are expected to largely remain to
the north of the effective warm sector. However, 30-35 kt of
deep-layer shear is forecast along the front over portions of the OH
Valley into the southern Mid-Atlantic, where some storm organization
appears possible with the primary hazard being damaging wind gusts.
Vertical shear will diminish with southwestward extent from the TN
Valley into the OK-TX Red River Valley; however, the presence of a
relatively deep, well-mixed boundary layer will be supportive of
sporadic damaging winds with isolated severe gusts.

...Raton Mesa Vicinity...

Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. The given environment will be supportive of
multicell and supercell storm modes with an associated risk for
large hail.

..Mead/Chalmers.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 12:46:06 2026

ACUS01 KWNS 101245
SWODY1
SPC AC 101244

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0744 AM CDT Thu Sep 10 2026

Valid 101300Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..Mosier/Lyons.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 16:16:26 2026

ACUS01 KWNS 101616
SWODY1
SPC AC 101615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Sep 10 2026

Valid 101630Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 16:42:30 2026

ACUS01 KWNS 101642
SWODY1
SPC AC 101615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Sep 10 2026

Valid 101630Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 19:41:18 2026

ACUS01 KWNS 101941
SWODY1
SPC AC 101940

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0240 PM CDT Thu Sep 10 2026

Valid 102000Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 19:54:58 2026

ACUS01 KWNS 101954
SWODY1
SPC AC 101940

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0240 PM CDT Thu Sep 10 2026

Valid 102000Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 00:46:58 2026

ACUS01 KWNS 110046
SWODY1
SPC AC 110045

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Thu Sep 10 2026

Valid 110100Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE SOUTHERN
TEXAS PANHANDLE INTO THE SOUTH PLAINS OF TEXAS...

...SUMMARY...
The threat for widely scattered large hail and a few severe wind
gusts is expected to continue through the remainder of the evening
into tonight over the southern Texas Panhandle into the South Plains
of Texas. Isolated damaging wind gusts appear possible over the
Mid-South and vicinity tonight.

...Texas Panhandle into the South Plains of Texas...

A cluster of strong to severe thunderstorms, including supercells,
is ongoing this evening between Amarillo and Lubbock amidst a
moderately unstable air mass with MLCAPE up to 1500 J/kg and
effective bulk shear of 40-50 kt, per the 00Z Amarillo sounding.
Hail in excess of two inches was reported earlier this evening near
Amarillo with a more recent wind gust of 65 mph near Plainview.
There is some signal in water vapor imagery for a weak disturbance
moving into the northern TX Panhandle, which may aid in sustaining
the ongoing storms through 03-05Z with a continued risk for large
hail and a few severe wind gusts.

...Mid-South...

Surface analysis indicates a convectively modified front from
west-central AR into middle TN, with a pocket of locally stronger
instability (i.e., MLCAPE up to 2000-2500 J/kg) near and to the
north of the boundary, per latest mesoanalysis. Forcing associated
with a subtle mid-level disturbance moving through south-central MO
is contributing to a gradual increase in storm coverage this evening
over far southeast MO into northeast AR. Time-lagged HRRR and RRFS
ensemble data suggest that a further increase in storm coverage is
possible late this evening into tonight over northern AR and
southeast MO into portions of northwest TN and western KY. Regional
VWPs indicate 0-6 km shear up to 30-35 kt, which may be sufficient
to support episodic storm organization with an associated risk for
isolated damaging wind gusts.

..Mead.. 09/11/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 05:28:36 2026

ACUS01 KWNS 110528
SWODY1
SPC AC 110526

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 AM CDT Fri Sep 11 2026

Valid 111200Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
MISSISSIPPI VALLEY INTO THE MID MISSOURI VALLEY...

...SUMMARY...
Scattered severe thunderstorms capable of large hail, potentially in
excess of two inches, a few tornadoes, and damaging wind gusts are
expected over portions of the upper Mississippi Valley Friday
afternoon into night. Storm development is more uncertain with
southward extent into the central Plains, where a conditional risk
for mainly large hail and severe wind gusts exists late Friday
afternoon through evening. Isolated occurrences of damaging wind
gusts appear possible from the Mid-South into the Carolinas and
Virginia.

...Synopsis...

A low-amplitude short-wave trough moving onto the Pacific Northwest
coast late this evening will progress through the northern Rockies
before reaching the ND/SK/MB border region by Friday evening.
Meanwhile, a preceding, lower-latitude disturbance is forecast to
move through SD into MN on Friday with strengthening mid/upper-level
winds and modest height falls accompanying these perturbations over
the northern Plains into the upper MS Valley. Elsewhere, a vorticity maximum/weak upper low will drift east from the Ozark Plateau into
the mid/lower MS Valley.

At the surface, an area of low pressure over western SD at 12Z
Friday is forecast to deepen slightly while developing into
northeast SD by afternoon, before subsequently weakening while
moving through central MN Friday night. The surface cyclone will
coincide with a cold front that will advance through the northern
Plains and the upper MS Valley. The trailing extension of the
boundary will move more slowly south into the mid MO Valley and
central High Plains. A dryline will precede the cold front with that
feature extending from eastern SD through central NE into western KS
by late afternoon. Elsewhere, a synoptic front modulated by
convective outflow is expected to stretch from the Mid-South into
the southern Mid-Atlantic on Friday afternoon.

...Upper Mississippi Valley into the mid Missouri Valley...

A low-level jet (LLJ) is forecast to strengthen through the day from
the mid MO Valley into the upper Midwest, enhancing the poleward
flux of an increasingly moist air mass ahead of the surface low and
attending frontal system. The moisture increase will occur beneath a
plume of steep mid-level lapse rates with MLCAPE increasing to
1500-2500+ J/kg by mid to late afternoon. Initial storm development
is expected at that time across portions of northern MN along or
ahead of the front, on the northern fringe of stronger capping.

Vertically veering wind profiles with 40-45 kt of deep-layer shear
will support supercells as the initial storm mode with the primary
hazard being large hail, some of which could exceed two inches. A
few tornadoes appear possible with any sustained supercells from
late afternoon into evening when the strengthening LLJ enhances
low-level shear with effective SRH increasing to 250-300 m2/s2.
Storms are expected to gradually grow upscale along the cold front
during the evening, at which point, the risk for damaging winds
should increase.

Severe weather potential becomes more conditional with southward
extent along the front and dryline in the mid MO Valley owing to
stronger capping and weaker height falls/forcing for ascent. The 00Z
models (convection-allowing and parameterized) indicate a relative
minimum in thunderstorm chances over eastern SD and southwest MN
with increasing probabilities from northeast NE into south-central
NE and north-central KS. Given surface-based storm initiation and
sustenance, CAPE-shear parameter space will favor supercells capable
of all hazards from eastern SD and southwest MN into northeast NE
and northwest IA, with generally a wind and hail threat farther
south along the NE-KS state line.

...Mid-South into the Carolinas and Virginia...

Areas of thunderstorms are expected to be ongoing at 12Z Friday from
the Ozark Plateau into the southern Mid-Atlantic. Stronger heating
on the southern fringe any lingering cloud cover will combine with boundary-layer dewpoints in the low to mid 70s F to yield MLCAPE of
1500-3000 J/kg by afternoon. Aided by forcing for ascent associated
with the mid-level trough approaching the mid/lower MS Valley,
thunderstorms are expected to increase in coverage and intensity
through the afternoon along and ahead of the composite surface
boundary. Weak vertical shear will limit storm organization with
mainly pulse storms expected. Nonetheless, the presence steep
low-level lapse rates and abundant moisture will be supportive of
wet microbursts capable of locally damaging wind gusts.

..Mead/Halbert.. 09/11/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 12:28:38 2026

ACUS01 KWNS 111228
SWODY1
SPC AC 111226

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0726 AM CDT Fri Sep 11 2026

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes should
occur late this afternoon into tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a conditional risk for large hail and
severe gusts will exist late this afternoon into the evening.

...Upper Midwest into the Central Plains...
Primary large-scale upper troughing will remain over central Canada
today, with an embedded mid-level shortwave trough forecast to eject
eastward over the northern Plains into the Upper Midwest through the
period. A modest surface response will occur across SD as the
shortwave trough ejects eastward, with most guidance suggesting a
sub-1000 mb low will develop into eastern SD by 12/00Z. A surface
cold front attendant to this low and the primary surface low over
central Canada will move east-southeastward across parts of the
Upper Midwest into the northern Plains, with a dryline extending
southward across the central Plains. A narrow corridor of 60s
surface dewpoints will be in place ahead of the cold front/dryline,
with diurnal heating aiding moderate destabilization along with
steepened mid-level lapse rates. Most guidance, including recent
NAM/RAP runs, show minimal MLCIN along/ahead of the front in far
northeast SD/western MN by 22-01Z. Convective development appears
likely in this time frame across this region, owing to sufficient
low-level convergence along the front coupled with forcing for
ascent associated with the mid-level shortwave trough.

Various NAM/RAP forecast soundings show strongly veering and
gradually strengthening winds with height through low/midlevels, and
35-45 kt of deep-layer shear will easily support organized
convection. Initial supercells should pose a threat for large hail
(isolated 2+ inches possible), but convective mode will probably
trend towards clustering fairly quickly given the presence of the
cold front and strengthening low-level jet this evening. Any
supercells that can remain at least semi-discrete into the early
evening may also have a tornado threat with greater low-level shear
forecast in this time frame. But, confidence in this scenario
occurring remains fairly low due to the mode transition expected.
Scattered severe/damaging winds should occur with any clusters or
bowing line segments that can develop and spread eastward through
the evening. However, the wind threat will likely wane with eastward
extent across MN into western WI by late this evening given the
narrow zone of destabilization forecast.

Convective initiation and overall thunderstorm coverage from
southeast SD/southwest MN into the central Plains are highly
uncertain and conditional this afternoon/evening, as the better
forcing for ascent with the shortwave trough will likely remain
across western/northern MN along and northeast of the surface low.
Still, a favorable thermodynamic environment and sufficient (25-35
kt) deep-layer shear would conditionally support severe hail/wind
with any thunderstorms that can develop and be sustained. There is
some signal in model guidance for successful convective initiation
across southern NE into northern KS late this afternoon/evening
where hotter surface temperatures are forecast. The southern extent
of the Marginal Risk has been adjusted to account for this
possibility, and the Slight Risk has generally been confined to
where greater confidence exists in robust thunderstorm development
(far northeast SD into western/northern MN).

...Mid-South into the Tennessee Valley/Carolinas and Virginia...
Two weak mid-level perturbations are evident in water vapor
satellite imagery this morning across the Southeast: one over AR,
and the other along the central Gulf Coast. These features will
generally track east-northeastward through the day, and should aid
additional thunderstorm development this afternoon. A stalled
surface front extending from the ArkLaTex into the TN Valley and
northeastward to VA should also provide a focus for thunderstorms.
Current expectations are for generally disorganized/pulse-type
convection to pose a threat for occasional damaging winds as diurnal
heating destabilizes the boundary layer and steepens low-level lapse
rates. But, modestly enhanced mid-level flow across parts of the
Mid-South and VA could promote loosely organized clusters with some
damaging wind threat as well.

..Gleason/Lyons.. 09/11/2026

$$

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From COD Weather Processor @1:2320/107 to All on Fri Sep 11 16:29:36 2026

ACUS01 KWNS 111629
SWODY1
SPC AC 111627

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Fri Sep 11 2026

Valid 111630Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes are
expected late this afternoon and tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a risk for large hail and severe
gusts may exist late this afternoon into the evening.

...Upper Midwest/central Plains...
An eastward-progressive belt of quasi-zonal westerlies exists over
the northern half of the CONUS, to the south of upper troughing over
the Canadian Prairies/central Canada, and the east of the amplifying
upper trough off the coastal Pacific Northwest. Weak frontal wave
development will occur from eastern South Dakota into Minnesota as a
cold front spreads eastward, with the front eventually overtaking a
pre-frontal trough/dryline across the central Plains.

A narrow corridor of 60s F surface dewpoints are in place ahead of
the cold front/dryline, with diurnal heating aiding moderate
destabilization along with steepened mid-level lapse rates. Minimal
MLCIN is expected along/ahead of the front in far northeast South Dakota/western Minnesota into/just after peaking heating. Convective development appears likely in this time frame across this region,
especially across Minnesota, owing to sufficient low-level
convergence along the front coupled with forcing for ascent
associated with the mid-level shortwave trough.

Strongly veering and gradually strengthening winds with height
through low/mid-levels, and 35-45 kt of deep-layer shear will easily
support organized convection. Initial supercells should pose a
threat for large hail (isolated 2+ inches possible), but convective
mode will probably trend towards clustering fairly quickly given the
presence of the cold front and strengthening low-level jet this
evening. Any supercells that can remain at least semi-discrete into
the early evening may also have a tornado threat with greater
low-level shear forecast in this time frame. Scattered
severe/damaging winds should occur with any clusters or bowing line
segments that can develop and spread eastward through the evening.
However, the wind threat will likely wane with eastward extent
across Minnesota into western Wisconsin by late this evening given
the narrow zone of destabilization forecast.

Farther southwest, convective initiation and overall thunderstorm
coverage from southeast South Dakota/southwest Minnesota
southwestward into Nebraska and northern Kansas are more uncertain
and probably more limited/conditional late this afternoon and
evening, as the better forcing for ascent with the shortwave trough
will remain regionally focused to the north. Still, a favorable
thermodynamic environment and sufficient (25-35 kt) deep-layer shear
would conditionally support severe hail/wind with any thunderstorms
that can develop and be sustained.

...Mid-South/Tennessee Valley/Carolinas and Virginia...
Multiple convectively augmented mid-level perturbations remain
evident at midday in satellite/radar imagery, including over the
Ozarks as well as the middle Gulf Coast in vicinity of southern
Alabama. A stalled surface front extending from the ArkLaTex
east-northeastward into the Tennessee Valley and Virginia will
provide a focus for thunderstorms. Generally speaking, expectations
are for generally disorganized/pulse-type convection to pose a
threat for occasional damaging winds as diurnal heating destabilizes
the boundary layer and steepens low-level lapse rates. However, a
modest enhancement to mid-level flow across parts of the Mid-South
(25 kt mid-levels per Little Rock AR WSR-88D VWP), as well as
Virginia, could promote a couple of loosely organized clusters with
a bit more of a focused damaging wind threat.

..Guyer/Weinman.. 09/11/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 20:02:50 2026

ACUS01 KWNS 112002
SWODY1
SPC AC 112000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Fri Sep 11 2026

Valid 112000Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes are
expected late this afternoon and tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a risk for large hail and severe
gusts may exist late this afternoon into the evening.

...20Z Update...
The ongoing forecast remains mostly on track with most areas
remaining unchanged. Given the signal for the cold front to push
into northern Kansas by early Saturday morning, along with at least
a modest low-level jet, marginal wind/hail probabilities have been
extended into more of central Kansas for the conditional potential
of severe storms overnight.

..Wendt.. 09/11/2026

.PREV DISCUSSION... /ISSUED 1127 AM CDT Fri Sep 11 2026/

...Upper Midwest/central Plains...
An eastward-progressive belt of quasi-zonal westerlies exists over
the northern half of the CONUS, to the south of upper troughing over
the Canadian Prairies/central Canada, and the east of the amplifying
upper trough off the coastal Pacific Northwest. Weak frontal wave
development will occur from eastern South Dakota into Minnesota as a
cold front spreads eastward, with the front eventually overtaking a
pre-frontal trough/dryline across the central Plains.

A narrow corridor of 60s F surface dewpoints are in place ahead of
the cold front/dryline, with diurnal heating aiding moderate
destabilization along with steepened mid-level lapse rates. Minimal
MLCIN is expected along/ahead of the front in far northeast South Dakota/western Minnesota into/just after peaking heating. Convective development appears likely in this time frame across this region,
especially across Minnesota, owing to sufficient low-level
convergence along the front coupled with forcing for ascent
associated with the mid-level shortwave trough.

Strongly veering and gradually strengthening winds with height
through low/mid-levels, and 35-45 kt of deep-layer shear will easily
support organized convection. Initial supercells should pose a
threat for large hail (isolated 2+ inches possible), but convective
mode will probably trend towards clustering fairly quickly given the
presence of the cold front and strengthening low-level jet this
evening. Any supercells that can remain at least semi-discrete into
the early evening may also have a tornado threat with greater
low-level shear forecast in this time frame. Scattered
severe/damaging winds should occur with any clusters or bowing line
segments that can develop and spread eastward through the evening.
However, the wind threat will likely wane with eastward extent
across Minnesota into western Wisconsin by late this evening given
the narrow zone of destabilization forecast.

Farther southwest, convective initiation and overall thunderstorm
coverage from southeast South Dakota/southwest Minnesota
southwestward into Nebraska and northern Kansas are more uncertain
and probably more limited/conditional late this afternoon and
evening, as the better forcing for ascent with the shortwave trough
will remain regionally focused to the north. Still, a favorable
thermodynamic environment and sufficient (25-35 kt) deep-layer shear
would conditionally support severe hail/wind with any thunderstorms
that can develop and be sustained.

...Mid-South/Tennessee Valley/Carolinas and Virginia...
Multiple convectively augmented mid-level perturbations remain
evident at midday in satellite/radar imagery, including over the
Ozarks as well as the middle Gulf Coast in vicinity of southern
Alabama. A stalled surface front extending from the ArkLaTex
east-northeastward into the Tennessee Valley and Virginia will
provide a focus for thunderstorms. Generally speaking, expectations
are for generally disorganized/pulse-type convection to pose a
threat for occasional damaging winds as diurnal heating destabilizes
the boundary layer and steepens low-level lapse rates. However, a
modest enhancement to mid-level flow across parts of the Mid-South
(25 kt mid-levels per Little Rock AR WSR-88D VWP), as well as
Virginia, could promote a couple of loosely organized clusters with
a bit more of a focused damaging wind threat.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 00:30:48 2026

ACUS01 KWNS 120030
SWODY1
SPC AC 120028

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0728 PM CDT Fri Sep 11 2026

Valid 120100Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER FAR EASTERN
SOUTH DAKOTA INTO PORTIONS OF MINNESOTA...

...SUMMARY...
Widely scattered severe thunderstorms capable of producing large
hail up to two inches, damaging winds, and a couple of tornadoes
will continue through the remainder of the evening into tonight from
far eastern South Dakota into portions of Minnesota. Isolated
occurrences of severe wind gusts and large hail remain possible over
parts of the central Plains tonight.

...Upper Mississippi Valley into the central Plains...

A broken band of thunderstorms has recently developed from far
eastern SD into north-central MN within a relatively narrow
instability axis preceding a surface cold front and dryline. The
presence of steep mid-level lapse rates (per 00Z ABR sounding) atop boundary-layer dewpoints in the mid to upper 60s F is resulting in
MLCAPE up to 1500-2000 J/kg. As mentioned above, the corridor of
stronger instability and minimal capping is rather narrow
longitudinally, which suggests the severe weather threat may remain
somewhat limited spatially into tonight.

The KFSD VWP is likely indicative of the ambient kinematic
environment, which features 35-40 kt of deep-layer shear and
relatively strong low-level shear, supportive of a supercell storm
mode with the primary hazard being large hail up to two inches.
Tornado potential will be conditional on the maintenance of
semi-discrete supercells residing within the narrow axis of minimal
convective inhibition. Damaging wind potential may tend to increase
by late evening as thunderstorms evolve into line segments.

Additional storms appear possible late this evening into tonight
ahead of a southeastward-moving cold front over portions of eastern
and central NE. Similar to locations to the north, a relatively
narrow zone of minimal convective inhibition and moderate
instability exists ahead of the front, which leads to uncertainty in
the areal coverage and duration of the threat. Severe wind gusts
will be the primary hazard with any surface-based storms that can
become established, though isolated occurrences of large hail are
also possible.

..Mead.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 05:26:28 2026

ACUS01 KWNS 120525
SWODY1
SPC AC 120524

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 AM CDT Sat Sep 12 2026

Valid 121200Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS...OZARK PLATEAU...AND UPPER OHIO
VALLEY...

...SUMMARY...
Widely scattered severe storms capable of large hail up to two
inches and damaging wind gusts appear possible over portions of the
central and southern Plains into the Ozark Plateau on Saturday into
Saturday night. Isolated occurrences of damaging wind gusts may also
occur over portions of the upper Ohio Valley Saturday afternoon.

...Synopsis...

A belt of enhanced mid/upper-level flow will persist over the
north-central U.S., downstream from a vigorous upper low moving into
the Pacific Northwest. Meanwhile, a lower-latitude trough over the
lower OH and lower MS Valleys Saturday morning is forecast to weaken
while progressing through the OH and TN Valleys. At the surface, a
cold front will advance through the upper Great Lakes with the
trailing extension of the boundary pushing south through the lower
MO Valley and central Plains before linking with a surface low over
the southern High Plains.

...Central and Southern Plains into the Ozark Plateau...

Persistent capping across the pre-frontal warm sector and generally
weak forcing for ascent lead to considerable uncertainty in
thunderstorm evolution through the forecast period. A number of the
00Z models (both convection-allowing and parameterized) indicate
areas of thunderstorms ongoing at 12Z Saturday over the central
Plains within a zone of modest warm advection and moisture transport
associated with a weakening low-level jet. One possible scenario is
for the continued southeast movement of the early-day storms through
eastern KS and southwest MO into portions of OK and AR by afternoon,
where a hot and moderate to strongly unstable air mass (i.e., MLCAPE
up to 2000-3000 J/kg) is forecast to develop. The instability
combined with around 30 kt of deep-layer shear would support
organized cold pool development in that scenario with an associated
risk for damaging wind gusts and large hail.

Renewed storm development appears possible from late morning into
afternoon from north of the front in south-central and southeast NE
to along or ahead of the front in northeast KS. Up to 40 kt of
deep-layer shear will coincide with the northern extension of the
stronger instability mentioned above to support supercell storm
modes with an associated risk for large hail up to two inches and
damaging wind gusts.

A separate thunderstorm regime may also evolve by mid to late
afternoon over the eastern OK and TX Panhandles into western OK in
the vicinity of the surface low and southward-sagging front.
Forecast soundings indicate a deep, well-mixed boundary layer, which
will be supportive of a few severe wind gusts and isolated large
hail.

Confidence in any of the above scenarios/regimes remains too low to
include Slight Risk wind and hail probabilities with this forecast.
A categorical upgrade is possible in subsequent Day 1 outlooks once
finer-scale details become more clear.

...Upper Ohio Valley...

A spatially narrow corridor of stronger heating and resultant
instability (MLCAPE up to 1500-2000 J/kg) is forecast to develop
during the afternoon between denser clouds and precipitation to the
west, and a backdoor front/stationary boundary to the east.
Thunderstorms are expected to increase in coverage and intensity
through the afternoon within the instability axis, aided by
increased forcing for ascent associated with the approaching
mid-level trough. While mid-level lapse rates are expected to remain
relatively weak, deep-layer shear increasing to 30-35 kt coupled
with steepening low-level lapse rates suggests the potential for
some storm organization with the primary hazard being damaging wind
gusts. Backed low-level winds in the vicinity of the surface front
will boost low-level shear slightly and a brief tornado cannot be
ruled out as mature storms approach the frontal zone from the west.

..Mead/Halbert.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

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