ACUS48 KWNS 040904
SWOD48
SPC AC 040903

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0403 AM CDT Mon Aug 04 2025

Valid 071200Z - 121200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
During the late week time-frame, a mid-level trough is forecast to
develop over the Pacific Northwest and move eastward into the
northern Plains. As the system approaches, a moist and unstable
airmass is forecast across the northern Plains and upper Mississippi
Valley. On Thursday, a lead shortwave trough is forecast to move
across the northern Plains. Large-scale ascent associated with the
trough could result in a cluster of storms with an isolated severe
threat from Thursday evening into the overnight period. Isolated to
scattered thunderstorms may again develop Friday afternoon and
evening, as the exit region of a mid-level jet moves across the
northern Plains. As instability becomes maximized on Friday
afternoon, a severe threat will be possible across parts of the
Dakotas and Minnesota. Large hail and severe gusts will be the
primary threats. The models are in reasonably good agreement on the
timing of the mid-level system. For this reason, have added a 15
percent into the northern Plains to coincide with the projected
locations of the instability axis and mid-level jet.

On Saturday, the mid-level trough is forecast to move into the
northern Plains, as a belt of southwesterly flow shifts eastward
across the Upper Midwest. Thunderstorm development will be possible
in the afternoon and evening, to the east of a front within an
unstable airmass in the upper Mississippi Valley. Moderate
deep-layer shear will again support an isolated severe threat across
the region.

...Sunday/Day 7 and Monday/Day 8...
The front is forecast to move southeastward into the upper
Mississippi Valley on Sunday. This will favor thunderstorm
development along a corridor from Iowa northeastward into Wisconsin,
where an isolated severe threat will be possible in the afternoon
and evening. On Monday, forecasts suggest the instability axis will
remain in a similar location. For this reason, a severe threat could
again affect this same corridor. Due to the extended range in the
forecast, there is some uncertainty concerning this scenario early
next week.

..Broyles.. 08/04/2025

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ACUS48 KWNS 050900
SWOD48
SPC AC 050858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Tue Aug 05 2025

Valid 081200Z - 131200Z

...DISCUSSION...
...Friday/Day 4 to Sunday/Day 6...
On Friday, a mid-level trough and an associated speed max is
forecast to move into the northern Plains. At the surface, a moist
airmass will be in place over much of the northern Plains, where
surface dewpoints are likely to be in the lower to mid 70s F. As
surface temperatures warm during the day, moderate to strong
instability is expected to develop. Along the northwestern edge of
this unstable airmass, thunderstorms should form in parts of central
and eastern North Dakota. Convective coverage is forecast to expand
southward into South Dakota during the evening. Moderate to strong
deep-layer shear associated with the speed max will be favorable for
a severe threat during the afternoon and evening. Supercells with
large hail, severe wind gusts and a tornado threat will be possible.


On Saturday, the mid-level trough and associated cold front are
forecast to move eastward into the upper Mississippi and mid
Missouri Valleys. Thunderstorms are forecast to be ongoing along and
near the front during the morning, with additional thunderstorm
development taking place further southeast in the afternoon.
Moderate instability and deep-layer shear is forecast across much of
the region, suggesting that a severe threat will again be possible.
There is some uncertainty as to how much the airmass will be
negatively affected by the morning convection. Also, model forecasts
suggest that the greatest convective potential will be during the
overnight period on Saturday. For this reason, will not add a threat
area for Saturday at this time.

On Sunday, a mid-level trough is forecast to move across the
north-central U.S., being positioned from the northern Plains to the
central Rockies by afternoon. A moderately unstable airmass is
forecast further to the east, from the upper Mississippi Valley
southward into the mid Missouri Valley. An isolated severe threat
will be possible Sunday afternoon along and near the instability
axis. However, the mid-level trough is forecast to remain well to
the west of the instability axis, which should limit large-scale
ascent over the unstable airmass, helping to keep any severe threat
isolated.

...Monday/Day 7 and Tuesday/Day 8...
A low-amplitude mid-level trough is forecast to move into the upper
Mississippi Valley on Monday, and into the western Great Lakes on
Tuesday. Further southwest, a mid-level low is forecast across the
central Plains. Thunderstorms will be possible on Monday and Tuesday
afternoon, along the northern edge of a moist airmass from the
central Plains northeastward to the Great Lakes. Model forecasts
suggest that deep-layer shear will be relatively weak. Although
convective coverage and any associated severe threat will likely
remain isolated, a few marginally severe storms could occur in areas
that heat up the most.

..Broyles.. 08/05/2025

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ACUS48 KWNS 060855
SWOD48
SPC AC 060854

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Wed Aug 06 2025

Valid 091200Z - 141200Z

...DISCUSSION...
...Saturday/Day 4 to Monday/Day 6...
A mid-level trough will move across the northern Plains on Saturday,
as a cold front advances southeastward into the upper Mississippi
and mid Missouri Valleys. Moderate to strong instability should be
in place ahead of the front by afternoon from eastern Nebraska
northeastward into Wisconsin. Thunderstorm development is expected
to take place along parts of the front from the afternoon into the
evening, with the greatest convective coverage over the upper
Mississippi Valley. A few storms could be severe, with large hail
and isolated damaging wind gusts expected to be the primary threats.


On Sunday, another mid-level trough is forecast to move into the
central and northern Plains, as a moist and unstable airmass remains
in place ahead of the front from the mid Missouri Valley
northeastward upper Mississippi Valley. Thunderstorms will again be
possible ahead of the trough near an axis of moderate instability
during the afternoon and evening. Some model forecasts suggest the
strongest instability will not be co-located with the greatest
convective potential. Although a severe threat may develop across
parts of the region, this would negatively affect severe threat
magnitude.

The mid-level trough is forecast to shift eastward across the
north-central U.S. on Monday, as a cold front advances southeastward
across the central Plains and Upper Midwest. Isolated severe
thunderstorms will again be possible ahead of the front near an axis
of moderate instability. However, large-scale ascent will be
somewhat limited across much of the region, suggesting the
convective potential and resulting severe threat should remain
isolated.

...Tuesday/Day 7 and Wednesday/Day 8...
From Tuesday into Wednesday, the mid-level trough and an associated
cold front is forecast to advance eastward from the north-central
U.S. into the Northeast. Along and ahead of the front each afternoon
and evening, strong thunderstorms will be possible. However, the
models are forecasting less instability and a more disorganized
pattern compared to previous days, suggesting that any severe threat
will remain localized.

..Broyles.. 08/06/2025

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ACUS48 KWNS 070845
SWOD48
SPC AC 070843

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CDT Thu Aug 07 2025

Valid 101200Z - 151200Z

...DISCUSSION...
...Sunday/Day 4 to Tuesday/Day 6...
A persistent shortwave mid-level trough is forecast to remain over
the central U.S. from Sunday to Tuesday. During this time period, a
moist and unstable airmass is forecast to be in place from the
central Plains northeastward into the Great Lakes. It appears that
large-scale ascent will be weak across most of this airmass, which
will result in limited convective coverage. Although instability and
deep-layer shear should be sufficient for an isolated severe threat
each afternoon, mainly in areas that heat up the most, any potential
should remain localized.

Further north into the northern Plains, low-level moisture is
forecast to increase by midweek. In response, a moderately unstable
airmass could develop by Tuesday afternoon. In spite of this, warm
air aloft and limited large-scale ascent should keep convective
coverage very isolated. This will likely limit any related severe
threat.

...Wednesday/Day 7 and Thursday/Day 8...
From Wednesday into Thursday, a mid-level trough is forecast to move
across the northwestern U.S. Ahead of this system, a cold front is
forecast to advance southeastward across the northern Plains.
Thunderstorms would be possible near the front across the Dakotas
Wednesday afternoon, and in the upper Mississippi Valley Thursday
afternoon. An isolated severe threat would be possible for both
days. However, details concerning any potential scenario, including
the timing of the front, is highly uncertain at this time.

..Broyles.. 08/07/2025

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ACUS48 KWNS 080823
SWOD48
SPC AC 080822

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0322 AM CDT Fri Aug 08 2025

Valid 111200Z - 161200Z

...DISCUSSION...
A weak upper trough over the north-central U.S. on Monday/D4 will
move into the upper Great Lakes on Tuesday/D5, then eject into
eastern Canada by Wednesday/D6. From D6 through Friday/D8, another
wave is forecast to develop over the Pacific Northwest, and move
across the northern Rockies.

At the surface, a moist air mass will remain over much of the
central and eastern states, with minimal surface focus. However,
daily areas of thunderstorms, some with gusty winds, are likely to
occur from the upper Great Lakes to the southern Plains for
Monday/D4 into Tuesday/D5, and then into the OH/TN Valleys and
Northeast thereafter.

Perhaps by D7/D8, the northern Rockies trough will interact with
stronger instability over the northern Plains with a wind or hail
threat, but predictability is low this far out for such a minimal
system.

..Jewell.. 08/08/2025

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ACUS48 KWNS 090819
SWOD48
SPC AC 090817

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0317 AM CDT Sat Aug 09 2025

Valid 121200Z - 171200Z

...DISCUSSION...
A shortwave trough will move from the northern Plains into the
Northeast during the Tuesday/D4 to Wednesday/D5 time frame, with an
initial push of drier air southward across the Midwest/Great Lakes.
Stronger instability is forecast to redevelop by Thursday/D6 and
beyond as a low-amplitude upper trough moves across the northern
Rockies and Plains and increasing southerly low-level winds bring
dewpoints into the mid 70s F northward across the Mid MO/Upper MS
Valleys. This may yield one or more severe events across parts of
the northern Plains to upper MS Valley, but confidence is low.

..Jewell.. 08/09/2025

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ACUS48 KWNS 100825
SWOD48
SPC AC 100824

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0324 AM CDT Sun Aug 10 2025

Valid 131200Z - 181200Z

...DISCUSSION...
From Wednesday/D4 into Thursday/D5, a shortwave trough is forecast
to move from the Pacific Northwest across MT and over the far
northern Plains, with an upper speed max developing into southern SK
and MB. In advance of this trough, a leading trough affecting the
Great Lakes region will also lift northeastward, with height rises
and a warming pattern across parts of the Plains and upper Midwest.
The combination of increasing dewpoints and the upper trough
glancing the region may result in some manner of severe risk late
Thursday/D5, and most likely from parts of ND into northern MN, and
in evening/overnight MCS form. Future model trends will be monitored
for a possible risk area.

From Friday/D6 onward, predictability decreases with the motion of
the aforementioned upper wave. However, large instability is likely
to again build across the Mid MO/Upper MS Valleys, and at least
sporadic severe storms cannot be ruled out from the northern High
Plains eastward toward the Upper Great Lakes.

..Jewell.. 08/10/2025

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ACUS48 KWNS 110853
SWOD48
SPC AC 110852

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0352 AM CDT Mon Aug 11 2025

Valid 141200Z - 191200Z

...DISCUSSION...
On Thursday/D4, a shortwave trough is forecast to move from MT into
the northern Plains, with primary upper low well to the north. A
surface trough and cold front should push eastward across the
Dakotas as well, and extend roughly from MN into NE by Friday/D5
morning. Model spread is high regarding the amount of moisture
return and instability, with some models likely over-estimating real instability. In any case, storms appear most likely from ND into
northern MN, beneath 50+ kt midlevel westerlies. As such, a 15%
severe area has been introduced.

This wave will progress east/northeastward on Friday/D5, with a
front trailing southwestward perhaps from Lake Superior across WI/MN
and toward NE. A moist and unstable air mass will remain near and
south of any such boundary, but the position of said boundary may
depend on storms from the previous night, or possibly a continuation
of such storms. Predictability is therefore low on Friday/D5.

Beyond this time frame, it appears the storm track will shift
northward into Canada, with upper ridging over much of the CONUS.

..Jewell.. 08/11/2025

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ACUS48 KWNS 120812
SWOD48
SPC AC 120811

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0311 AM CDT Tue Aug 12 2025

Valid 151200Z - 201200Z

...DISCUSSION...
From Friday/D4 into Saturday/D5, an upper low will move from
Manitoba across Hudson Bay and into Quebec. Moderate midlevel
westerlies will exist over the far northern Plains to Upper Great
Lakes during this period, with gradual weakening. An upper high will
also be centered over the mid MS Valley, while a weak midlevel
trough with cool air aloft slowly departs the Great Basin.

At the surface, a front is forecast to stall on Friday/D4 from
northern NE across southern MN and into northern WI, with a moist
and unstable air mass remaining to the south. This front will remain
over roughly the same zone into Saturday/D5, and perhaps as late as
Sunday/D6.

Given that the moist and unstable air mass will persist over parts
of the northern Plains/Upper MS Valley, and minor ripples in the
flow are hinted at by several models, areas of storms are expected.
However, storm/MCS corridors are difficult to pinpoint this far out.
In general, the area from SD into WI will bear watching for wind
potential.

From Sunday/D6 onward, an upper ridge is expected to build over much
of the western and central states, with a reduction in severe
potential overall.

..Jewell.. 08/12/2025

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ACUS48 KWNS 130846
SWOD48
SPC AC 130844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Wed Aug 13 2025

Valid 161200Z - 211200Z

...DISCUSSION...
During the Saturday/D4 to Sunday/D5 time frame, a weak midlevel wave
may affect the far northern Plains to upper Great Lakes, rounding
the building upper ridge. Meanwhile, a boundary will exist roughly
from ND/MN into MI, with latitudinal uncertainty. A moist air mass
will remain across this zone, with periodic storm complexes
possible. Predictability is low but at least some wind risk may
develop across portions of this zone.

For the rest of the period through at least Wednesday/D8, a large
upper ridge is forecast to build over much of the West/Rockies, with
minimal severe risk.

..Jewell.. 08/13/2025

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ACUS48 KWNS 140828
SWOD48
SPC AC 140826

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0326 AM CDT Thu Aug 14 2025

Valid 171200Z - 221200Z

...DISCUSSION...
An upper ridge is forecast to build over the Plains and Rockies
through Tuesday/D6, with the upper high retrograding from the
central Plains to the Four Corners. East of the ridge axis,
northwest midlevel flow of 20-30 kt will persist over the upper MS
Valley/Great Lakes, with a large area of moisture and instability
roughly from MN/IA to IL/IN. This pattern should support corridors
of thunderstorms in the low-level warm advection zone, or along the
northern instability gradient through Tuesday/D6. While areas of
strong wind gusts will be possible, the overall severe probably is
less than the 15% threshold over this large zone.

The upper ridge may flatten over the northern Rockies/Plains beyond
D6, with perhaps an eventual northwest flow regime coinciding with
residual instability, supporting at least minimal severe potential
over the northern Plains.

..Jewell.. 08/14/2025

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ACUS48 KWNS 150845
SWOD48
SPC AC 150844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Fri Aug 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
At mid-levels, heights are forecast to rise across the north-central
states on Monday and Tuesday, as west-northwesterly flow remains
from parts of the northern Plains to the Eastern Seaboard.
Thunderstorm development will be possible each day along parts of a
front, which is forecast to be slow-moving and situated from the
northern Plains east-southeastward into the southern Great Lakes. An
isolated severe threat will be possible in the vicinity of the front
within a moderately unstable airmass on Monday from parts of South
Dakota eastward into the western Great Lakes. Storms with an
isolated severe threat will again be possible on Tuesday. The
greatest convective coverage is forecast to be further to the east
from the southern Great Lakes into the central Appalachians.

On Wednesday, isolated to scattered thunderstorms are expected over
parts of the mid Mississippi and lower Ohio Valleys. In this area,
large-scale ascent and deep-layer shear are forecast to be weak
suggesting the potential for severe storms will remain low.

...Thursday/Day 7 and Friday/Day 8...
On Thursday, a cold front is forecast to move into the northern
Plains. Thunderstorm development will be possible ahead of the front
along an axis of instability from parts of South Dakota into
northwestern Minnesota. An isolated severe threat may develop with
this activity during the afternoon and evening. The potential for
isolated severe is forecast to shift southeastward into the mid
Missouri upper Mississippi Valleys on Friday. However, uncertainty
is low at this range in the forecast period.

..Broyles.. 08/15/2025

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ACUS48 KWNS 160857
SWOD48
SPC AC 160856

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Sat Aug 16 2025

Valid 191200Z - 241200Z

...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5...
A mid-level ridge will build across the Rockies and northern High
Plains during the middle part of the week. At the surface, a front
will advance slowly southward into the lower Missouri and mid
Mississippi Valleys. A post-frontal airmass will remain over the
upper Mississippi and Great Lakes region. On the southern and
western periphery of this airmass, moderate instability is forecast
to develop each afternoon. Limited large-scale ascent is expected to
keep convective coverage isolated. In spite of relatively weak
deep-layer shear along much of the instability corridor, steep low
to mid-level lapse rates will be in place and could be enough for a
marginal severe threat in areas that destabilize the most.

...Thursday/Day 6 and Saturday/Day 8...
Mid-level zonal flow is forecast to develop on Thursday over much of
the north-central and northwestern U.S., as a ridge moves
southeastward into the western Great Lakes. A pocket of moderate
instability is forecast to develop ahead of a cold front on Thursday
in the northern Plains. Limited large-scale ascent should keep
convective coverage isolated. Although deep-layer shear is forecast
to be modest, any cell that can develop and persist near the
stronger instability in the late afternoon and early evening could
obtain an isolated severe threat.

On Friday an Saturday, a cold front is forecast to move
southeastward across the north-central U.S. Near and ahead of the
front, isolated thunderstorms will be possible each afternoon from
the upper Mississippi Valley into the Great Lakes region. The
combination of instability and shear could be sufficient for an
isolated severe threat. However, considerable uncertainty exists at
this range in the forecast.

..Broyles.. 08/16/2025

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ACUS48 KWNS 170855
SWOD48
SPC AC 170854

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Sun Aug 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...Wednesday/Day 4 to Friday/Day 6...
On Wednesday, a mid-level ridge will likely be in place across the
northern Plains. At the surface, a front is forecast to be located
over the Ozarks and lower Ohio Valley. Moderate instability is
expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer
shear should be weak, suggesting a severe threat is unlikely.

On Thursday, a mid-level shortwave trough and an associated cold
front are forecast to move eastward into the northern Plains. An
axis of moderate instability is forecast ahead of the front. This
combined with moderate deep-layer shear could be enough for an
isolated severe threat during the afternoon and evening, mainly over
eastern North Dakota and northwestern Minnesota.

The front and its associated shortwave trough are forecast to move
into the upper Mississippi and mid Missouri Valleys on Friday.
Moderate instability appears likely to develop ahead of the front
during the afternoon. Along and near the instability axis, the
greatest potential for thunderstorm development could occur in the
central Plains within northwest mid-level flow. An isolated severe
threat will be possible during the late afternoon and early evening.

...Saturday/Day 7 and Sunday/Day 8...
On Saturday and Sunday, an upper-level trough is forecast to remain
over the Great Lakes region. Ahead of the trough, an axis of
instability is forecast to develop in the central Appalachians,
where isolated to scattered thunderstorms will be possible each
afternoon. Moderate deep-layer shear could be sufficient for an
isolated wind-damage threat, mainly in the late afternoon as
low-level lapse rates become steep.

..Broyles.. 08/17/2025

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ACUS48 KWNS 180854
SWOD48
SPC AC 180852

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0352 AM CDT Mon Aug 18 2025

Valid 211200Z - 261200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
On Thursday, a subtle shortwave trough is forecast to move eastward
across the northern Plains. An axis of moderate instability will
likely develop by afternoon ahead of the front across the eastern
Dakotas and northwest Minnesota. Scattered storms could develop
during the afternoon near the instability axis, with an isolated
severe threat possible.

On Friday, the front is forecast to move southeastward toward the
upper Mississippi and mid Missouri Valleys, as an axis of
instability develops during the afternoon. Isolated thunderstorms
will be possible near the instability axis, but the severe potential
is expected to remain localized, mostly due to minimal convective
coverage.

On Saturday, the front is forecast to move across the Great Lakes
region, extending west-southwestward into the central U.S. Isolated
storms with a potential for localized severe will again be possible
in the afternoon ahead of the front. Due to a lack of large-scale
ascent, cell coverage is expected to be very isolated.

...Sunday/Day 7 and Monday/Day 8...
From Sunday into Monday, an upper-level trough and an associated
cold front is forecast to move across the eastern U.S. Thunderstorm
development will be possible ahead of the front Sunday afternoon in
the central Appalachians, and along parts of the middle to upper
Atlantic Seaboard on Monday afternoon. Instability ahead of the
front is expected to remain weak in most areas during this period,
suggesting any severe threat will remain localized.

..Broyles.. 08/18/2025

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ACUS48 KWNS 190850
SWOD48
SPC AC 190849

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0349 AM CDT Tue Aug 19 2025

Valid 221200Z - 271200Z

...DISCUSSION...
...Friday/Day 4 to Sunday/Day 6...
On Friday, a mid-level shortwave trough and an associated cold front
is forecast to move into the upper Mississippi Valley. An axis of
moderate instability will likely develop by afternoon ahead of the
front from the western Great Lakes southwestward into the mid
Missouri Valley. Due to limited large-scale ascent, convective
coverage near the instability axis is expected to be very isolated.
A marginal risk will be possible with cells that develop close
enough to the instability axis.

On Saturday, the front is forecast to move through the Great Lakes
region, extending southward into the central Plains. Instability
will again develop ahead of the front, but convective initiation
should remain isolated due to a lack of large-scale ascent. The area
with the greatest potential for a marginal severe threat would be
over the central Great Lakes ahead of a shortwave trough.

The shortwave trough is forecast to amplify over the Great Lakes
region on Sunday, as the cold front advances through the lower Great
Lakes and Ohio Valley. Instability will increase during the day
ahead of the front over the central Appalachians with scattered
thunderstorms developing during the afternoon. Deep-layer shear
should be strong enough for an isolated wind-damage threat, mainly
in areas where instability is stronger.

...Monday/Day 7 and Tuesday/Day 8...
A cold front is forecast to advance towards the Eastern Seaboard on
Monday. Scattered thunderstorms will be possible Monday afternoon
ahead of the front from New England southward into the Mid-Atlantic.
Although moderate deep-layer shear is forecast, instability should
remain weak, suggesting any severe threat will be marginal. Although uncertainty is substantial at this extended range, the models keep a
relatively dry post-frontal airmass over much of the central and
eastern U.S on Tuesday. Along the southern periphery of this
airmass, isolated thunderstorms will be possible in the southern
Plains and Ark-La-Tex Tuesday afternoon. However, weak instability
is expected to limit severe threat potential.

..Broyles.. 08/19/2025

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ACUS48 KWNS 200804
SWOD48
SPC AC 200803

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0303 AM CDT Wed Aug 20 2025

Valid 231200Z - 281200Z

...DISCUSSION...
...D4/Saturday - D6/Monday...
On D4/Saturday, a seasonably strong cold front will move across
parts of the south-central Great Plains into the mid MS Valley and
southern Great Lakes region, as a deep mid/upper-level trough
becomes established over much of the central/eastern CONUS. Somewhat
favorable deep-layer flow/shear could support strong to locally
severe storms along the front, though generally modest instability
may tend to limit the magnitude of the severe threat. Strong storms
may also develop within a post-frontal regime across parts of the
central High Plains.

The cold front will make further south/east progress on D5/Sunday,
and locally strong storms may develop from parts of the Northeast
into the central/southern Appalachians. Generally weak instability
may tend to limit coverage of the organized severe threat. Strong
storms may also develop again within a post-frontal regime across
parts of the central/southern High Plains.

The cold front may tend to slow down by D6/Monday across parts of
the Mid Atlantic and Northeast, though guidance begins to diverge
regarding the evolution of the deep upper trough and potential for
surface low development off of the Mid Atlantic coast. Some
potential for strong storms could again evolve along the front, from
parts of New England into the Mid Atlantic.

...D7/Tuesday - D8/Wednesday...
While predictability continues to wane regarding the details,
extended-range guidance generally depicts persistence of the eastern
CONUS upper trough into the middle of next week, though it may begin
to shift eastward with time. In the wake of the cold frontal
passage, an expansive surface ridge is forecast to maintain
generally stable conditions for most areas east of the Rockies,
resulting in limited potential for organized severe storms.

..Dean.. 08/20/2025

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