AWUS01 KWNH 260614
FFGMPD
CAZ000-261000-

Mesoscale Precipitation Discussion 1277
NWS Weather Prediction Center College Park MD
113 AM EST Fri Dec 26 2025

Areas affected...western Transverse Ranges / southern CA

Concerning...Heavy rainfall...Flash flooding likely

Valid 260612Z - 261000Z

SUMMARY...Localized flash flooding is likely to continue across
the western Transverse Ranges through 10Z (2 AM PST). Peak hourly
rainfall of 0.5 to 1.0 inches and additional rainfall over the
next 4 hours of 1 to 2 inches is expected, mainly from eastern
Santa Barbara into Ventura counties.

DISCUSSION...MRMS reflectivity and local gauge reports showed
moderate to heavy rain continued to track across the Channel
Islands into the western Transverse Ranges. Hourly rainfall has
varied between 0.5 and 1.0 inches since 00Z and 3-hr totals ranged
from roughly 0.75 to 1.5 inches ending 06Z, mainly within central
Ventura County. This region of the western Transverse Ranges has
been situated within a relative max in precipitable water values
between 1.0 and 1.2 inches with a localized max observed on OSPO
Layered PW imagery from the surface to ~500 mb pointed into the
western Transverse Ranges. 850-700 mb layer winds were from the S
to SSW at 25-40 kt with little change over the past few hours. The
00Z VBG sounding and more recent aircraft-derived soundings showed
instability was weak (MLCAPE less than or equal to 250 J/kg) and
shallow, limiting lightning potential.

Nearly stationary to perhaps slow eastward translation is forecast
for the moisture axis through 10Z, out ahead of a larger scale
mid/upper level trough axis over the eastern Pacific. Therefore,
similar ingredients should remain in place for the region with
850-700 mb winds between 25-40 kt supporting IVT values between
300-500 kg/m/s. Weak/shallow instability combined with orographic
ascent into the terrain will continue to favor peak hourly
rainfall of 0.5 to 1.0 inches. Additional rainfall through 10Z of
1-2 inches is expected (mainly within eastern Santa Barbara into
Ventura County) which is likely to maintain localized flash
flooding due to saturated soils and the majority of additional
rainfall becoming runoff.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7xdk377ew3-HfJXl6wWFOeZ5TCj1i389a59mUWjUuYeZNMCESE3gRtvArR_MIkdiH-sG= PqIOgdVI09d7-rdd3wKjnfM$ for graphic product...

ATTN...WFO...HNX...LOX...

ATTN...RFC...RSA...NWC...

LAT...LON 35222013 34881960 34961930 34941907 34771869=20
34691858 34181855 33921903 34241965 34402042=20
34842055=20

=3D =3D =3D
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AWUS01 KWNH 260859
FFGMPD
CAZ000-261800-

Mesoscale Precipitation Discussion 1278
NWS Weather Prediction Center College Park MD
358 AM EST Fri Dec 26 2025

Areas affected...eastern Sacramento and San Joaquin Valleys into
Sierra Nevada Foothills

Concerning...Heavy rainfall...Flash flooding possible

Valid 260856Z - 261800Z

SUMMARY...A localized concern for additional flooding/flash
flooding will exist across portions of the Sacramento and San
Joaquin Valleys into the Sierra Nevada foothills through roughly
18Z. Peak hourly rainfall of 0.25 to 0.5 inches will be possible,
along with isolated hourly rainfall in excess of 0.5 inches.

DISCUSSION...Area radar imagery from 0845Z showed scattered
showers extending from the southern Sacramento Valley into the
northern San Joaquin Valley and eastward into the Sierra Nevada.
RAP analysis data and GPS-derived PWs ranged from 0.5 to 0.9
inches and 850-700 mb winds were 30-50 kt from the southwest. Low
level convergence has helped to focus a couple of SW to NE
oriented axes of showers with brief training and hourly rainfall
locally in excess of 0.5 inches per MRMS data. However,
surrounding gauge data and a vast majority of the region contained
peak hourly rainfall in the 0.25 to 0.50 inch range.

As a longwave upper level trough axis over the eastern Pacific
continues to translate eastward over the next 12 hours, total PW
values and 850-700 mb wind speeds are forecast to gradually lower
through 18Z which should have the effect of reducing higher hourly
rainfall potential. Snow levels varied from 5000 ft (northern
locations) to 8000 ft (southern locations) across the Sierra
Nevada and lowering of these values will occur as the upper trough
and colder air moves inland today. Until then however, localized
potential will remain for brief areas of heavy rain with an
additional 1-2 inches expected for some locations through 18Z. Due
to largely saturated soils in many locations from recent heavy
rainfall, additional heavy rainfall may lead to isolated
flood/flash flooding including the possibility of
landslides/mudslides.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!45fiue6QPyLVEwXtDh44fVO0rFR_8ROvcippO1XrAHZq_0Qqenz0GymvvfOdP477gfGz= 6QOztOkgmfg_Ye0ShoHvXw8$ for graphic product...

ATTN...WFO...HNX...STO...

ATTN...RFC...RSA...NWC...

LAT...LON 39552097 39132068 38832050 38532036 38082008=20
37741980 37371944 36931893 36101864 35491856=20
35401886 35721919 36281965 37002024 37722093=20
38682127 39302143=20

=3D =3D =3D
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AWUS01 KWNH 260937
FFGMPD
CAZ000-261900-

Mesoscale Precipitation Discussion 1279
NWS Weather Prediction Center College Park MD
437 AM EST Fri Dec 26 2025

Areas affected...northern CA coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 260935Z - 261900Z

SUMMARY...Isolated pockets of showers containing hourly rainfall
in the 0.25 to 0.5 inch range will continue a limited threat for
flooding/flash flooding across portions of the northern CA coast
through about 19Z.

DISCUSSION...0930Z water vapor imagery from GOES West showed a
mid-level low/vorticity max ~150 miles west of Cape Mendocino,
slowly advancing easGPS PWstward toward the northern CA coast.
GPS-derived PW values along the northern CA coast were 0.4 to 0.6
inches with 850-700 mb mean layer winds peaking near 40 kt from
the southwest. Increasing ascent ahead of the approaching low to
mid-level low and a subtle increase in IVT values (up to ~350
kg/m/s) are expected to bring yet another round of locally heavy
rain to the region through the remainder of the night into the
late morning.

Peak hourly rainfall of 0.25 to 0.50 inches will be possible as
the low approaches where weak and shallow MLCAPE up to ~500 J/kg
will be present per recent RAP forecasts. While these rates are
not typically a problem for the climatologically wet northern CA
coast, 7-day rainfall values are well above average and saturated
to nearly saturated soils could be sensitive to additional
rainfall. There will be potential for an additional inch or so of
rain through 19Z which may result in isolated landslides/mudslides
and/or urban flooding through the rest of the morning hours.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9Vw0XqGFU03csV-wfMBmpT0d0WXdFw0HrhGqWokZzyE-GZOTnBx0SSfHr-uFvB6MrfzX= sbgMD0ba3LMH2B4sF7Hvwd4$ for graphic product...

ATTN...WFO...EKA...MTR...STO...

ATTN...RFC...RSA...NWC...

LAT...LON 41252417 41232369 40852368 40352349 40052341=20
39722325 39282297 38762261 38562324 38892388=20
39392423 40222470 40722458 41112433=20

=3D =3D =3D
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AWUS01 KWNH 260943
FFGMPD
CAZ000-261900-

Mesoscale Precipitation Discussion 1279...Corrected
NWS Weather Prediction Center College Park MD
443 AM EST Fri Dec 26 2025

Corrected for typo and addition within first paragraph

Areas affected...northern CA coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 260935Z - 261900Z

SUMMARY...Isolated pockets of showers containing hourly rainfall
in the 0.25 to 0.5 inch range will continue a limited threat for
flooding/flash flooding across portions of the northern CA coast
through about 19Z.

DISCUSSION...0930Z water vapor imagery from GOES West showed a
mid-level low/vorticity max ~150 miles west of Cape Mendocino,
slowly advancing eastward toward the northern CA coast.
GPS-derived PW values along the northern CA coast were 0.4 to 0.6
inches with 850-700 mb mean layer winds peaking near 40 kt from
the southwest. While the corresponding surface low (992 mb) is
expected to weaken over the next 6-12 hours, increasing ascent
ahead of the approaching low to mid-level low and a subtle
increase in IVT values (up to ~350 kg/m/s) are expected to bring
yet another round of locally heavy rain to the region through the
remainder of the night into the late morning.

Peak hourly rainfall of 0.25 to 0.50 inches will be possible as
the low approaches where weak and shallow MLCAPE up to ~500 J/kg
will be present per recent RAP forecasts. While these rates are
not typically a problem for the climatologically wet northern CA
coast, 7-day rainfall values are well above average and saturated
to nearly saturated soils could be sensitive to additional
rainfall. There will be potential for an additional inch or so of
rain through 19Z which may result in isolated landslides/mudslides
and/or urban flooding through the rest of the morning hours.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7cUis92kCnAv1SYIX1BnkZfC8PO2z0muo6pS5fcSJJR-u8sv3L0rZAz7Zy5cTv2v7Azu= HfhxekhLcAPq-eldFmJi8x8$ for graphic product...

ATTN...WFO...EKA...MTR...STO...

ATTN...RFC...RSA...NWC...

LAT...LON 41252417 41232369 40852368 40352349 40052341=20
39722325 39282297 38762261 38562324 38892388=20
39392423 40222470 40722458 41112433=20

=3D =3D =3D
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AWUS01 KWNH 261035
FFGMPD
CAZ000-262000-

Mesoscale Precipitation Discussion 1280
NWS Weather Prediction Center College Park MD
535 AM EST Fri Dec 26 2025

Areas affected...Transverse Ranges to southern CA coast

Concerning...Heavy rainfall...Flash flooding likely

Valid 261034Z - 262000Z

SUMMARY...Areas of flash flooding will continue to affect portions
of the Transverse Ranges to the coast overnight into the late
morning hours. Hourly rainfall values of 0.5 to 1.0 inches
(locally higher) are likely which will maintain concerns for
impacts including landslides/debris flows and urban flooding.

DISCUSSION...1015Z radar imagery combined with local mesonet and
personal weather observations out of southern CA continued to show
areas of heavy rain within a narrow axis from the offshore waters
into mainly Ventura County. Hourly rainfall over 1 inch has been
observed in Ventura County with 3-hour totals of 1 to 2+ inches.
Local Wunderground gauges showed a couple of 30 minute rainfall
values over 0.5 inches within the past 2-3 hours near Ojai. These
rains were associated with a slow moving low level convergence
axis (remnant frontal boundary) that was oriented SSW to NNE
across Ventura County with PW values of 1.0 to 1.2 inches along
the coast and SSW 850-700 mb winds of 25-35 kt. Enhanced
divergence aloft may also be contributing to increased rainfall
intensity over the region, within the right-entrance region of a
150 kt jet streak aloft located over the Sierra Nevada.

Short term forecasts from the RAP show the low level convergence
axis and localized max in IVT values (up to 500 kg/m/s) slowly
advancing eastward over the next 6-9 hours. The result will be
localized high rain rates into the terrain, slowly shifting east,
given the favorable orthogonal orientation of the low level winds
to the axis of terrain. Hourly rainfall of 0.5 to 1.0+ inches
should advance eastward from Ventura County into Los Angeles
County through 15Z, possibly clearing Los Angeles County after
roughly 17Z. While the greatest potential for these higher rates
will be in the upslope favored terrain, shallow/weak instability
up to ~250 J/kg and short term training could support 0.5+ inch
hourly rainfall into the lower elevation urban areas as well.
Additional rainfall of 1 to 3 inches will be possible through 20Z
with potential for higher impact localized flash flooding over
sensitive burn scar locations in and around the Los Angeles metro.
Given heavy rain over the past 2 days, many locations contain
saturated soils with additional rainfall likely translating
directly into runoff. With this rainfall, there will be the
potential for dangerous travel and life-threatening impacts from
flooding.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-LZMtVUrN3iB_BZn50erNlgWuVFx2Gz-S7kpwOFNwFuPHWglkqMScRyfzLUyJeQPHOuE= N6Uq6vXg3BsEMf321O9Vt3M$ for graphic product...

ATTN...WFO...HNX...LOX...SGX...

ATTN...RFC...RSA...NWC...

LAT...LON 34811863 34471778 34201694 33671672 33361764=20
33471824 33761916 34071955 34451952 34761922=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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AWUS01 KWNH 281003
FFGMPD
MIZ000-INZ000-ILZ000-MOZ000-IAZ000-281600-

Mesoscale Precipitation Discussion 1281
NWS Weather Prediction Center College Park MD
502 AM EST Sun Dec 28 2025

Areas affected...northern MO/southeastern IA/north-central
IL/northwestern IN

Concerning...Heavy rainfall...Flash flooding possible

Valid 281000Z - 281600Z

SUMMARY...Isolated flash flooding will be possible from portions
of northern MO, southeastern IA into north-central IL and
northwestern IN through 16Z (10 AM CST). Rainfall of 1 to 2 inches
in an hour will be possible with isolated 3 to 6 hour totals of
2-3 inches.

DISCUSSION...0945Z radar imagery Midwest showed scattered showers
and embedded thunderstorms from northern MO, southern IA and
central IL, located north of a quasi-stationary front that
extended eastward from a 998 mb low just west of Salina, KS. SW to
WSW 850 mb winds of 30-50 kt were in place to the east of the
surface low with overrunning occurring atop the frontal boundary.
OSPO ALPW imagery showed low level moisture rapidly advecting
northward into the central U.S. beneath a plume of mid to upper
level moisture with origins in the tropical eastern Pacific. Total
PW values were estimated to be between 1.1 and 1.4 inches (SPC
mesoanalysis) from eastern KS into western IN, which equate to +4
to +5 standardized anomalies. The low level moisture return was
allowing for the northward advection of instability and erosion of
low level CINH amid 700-500 mb lapse rates of 7.0 to 7.5 C/km,
supporting MUCAPE of 500-1500 J/kg from eastern KS into
western/central MO via 09Z SPC mesoanalysis data. This change in
the thermodynamic environment has been reflected in recent
infrared satellite imagery showing bursts of colder cloud tops
over northern MO and far southern IA.

As the surface low over central KS moves eastward early this
morning, strengthening low level flow will translate into MO and
IL with 850 mb speeds locally exceeding 50 kt. Convergence at the
nose of 925-850 mb moisture transport will align WSW to ENE or
parallel to the mean steering flow. This will set up narrow axes
of heavy rainfall with training and potential for hourly rainfall
between 1 and 2 inches. The best overlap of low level convergence
with moisture/instability will be from northern MO into
north-central IL and northwestern IN through 16Z. Isolated
flash/urban flooding may result from 2-3 inches of rain in 2-3
hours. However, a lack of precipitation for this region of the
U.S. over the past couple of weeks (lower than average soil
moisture) and warmer than average temperatures (no/negligible
frost depth) should limit runoff. Therefore, any flash flood
concerns will likely be minor and remain limited to urban or
sensitive low lying areas.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_YG17WL1A4Ubdi67KFfO43e18ICjEG2HKhTFDp5vHXyUA4EeS62zo9t6AgrSOJoLIuD2= e1GJtSo6yTGe-RHU4VJf4oo$ for graphic product...

ATTN...WFO...DMX...DVN...EAX...ILX...IND...IWX...LOT...LSX...

ATTN...RFC...KRF...MSR...TIR...NWC...

LAT...LON 42178726 41658634 40918612 40448688 40038825=20
39629015 39199219 39289312 39699398 40409379=20
41329161 42118904=20

=3D =3D =3D
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AWUS01 KWNH 010958
FFGMPD
CAZ000-011800-

Mesoscale Precipitation Discussion 0001
NWS Weather Prediction Center College Park MD
457 AM EST Thu Jan 01 2026

Areas affected...Southern CA

Concerning...Heavy rainfall...Flash flooding possible

Valid 011000Z - 011800Z

SUMMARY...Flash flooding is possible from the Coastal Range to the
Transverse Ranges where soils remain sensitive and saturated.
Localized urban flash flooding around the greater Los Angeles
metro area is also possible this morning.

DISCUSSION...GOES-19 satellite imagery shows a compact 500mb low
embedded within an increasingly negative 200-500mb mean trough
located west of CA. This upper trough is working in concert with a
700mb ridge near Cabo San Lucas to direct a highly anomalous plume
of moisture into not only CA but much of the western U.S.. PWATs
along the CA coast this morning are topping 1.25" and are above
the 99th climatological percentile. IVT is also topping 500 kg/m/s
and winds are out of the SW, which is supportive of some upslope
enhancement along orthogonally-oriented terrain from the Coastal
Range on south and east through the Transverse Ranges. As the
triple point of an occluded low approaches, so will the nose of a
500mb jet streak and low-level winds will strengthen off the
coast. Steepening mid-level lapse rates are expected as the
upper-low approaches and 00Z HREF guidance does show as much as
250 J/kg of MUCAPE potentially available as far north as Big Sur
this morning as a result.

06Z HREF guidance shows high chance probabilities (>70%) for 6-hr
rainfall totals >2" between 12-18Z along the San Bernadino
Mountains and low-to-moderate chances (30-50%) along the San
Gabriel. These are the mountain ranges most susceptible to
potential flash flooding in wake of last week's significant flood
event and lingering burn scars. As the the dry slot quickly moves
in by 18Z, the core of the heaviest rainfall should move north and
east with only lingering upslope flow keeping periods of rain
around the Transverse and Peninsular Ranges. Given the low FFG's
and sensitive soils in the higher terrain, as well as locally
heavy rainfall rates around the highly urbanized Los Angeles metro
area, flash flooding is possible this New Year's Day morning. Note
that rock slides and debris flows are also possible in the
Transverse Ranges where soils and burn scars are highly sensitive.

Mullinax

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-pdJyxrIMrPLOD6igfuFQaU8Rv3UjlFuGAZequATOa06undIguDAQQi2SQYpTIG3hqbn= eJxporhP2q85F16qxrDgius$ for graphic product...

ATTN...WFO...HNX...LOX...MTR...SGX...

ATTN...RFC...RSA...NWC...

LAT...LON 36632190 36542164 36222137 35922107 35642076=20
35252039 35022004 34881962 34851903 34941860=20
34781831 34491824 34481790 34491738 34371706=20
34221696 34061748 33891770 33651837 33821908=20
34241954 34332017 34392067 35062099 35792164=20
36092200 36412207=20

=3D =3D =3D
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AWUS01 KWNH 011521
FFGMPD
CAZ000-012120-

Mesoscale Precipitation Discussion 0002
NWS Weather Prediction Center College Park MD
1020 AM EST Thu Jan 01 2026

Areas affected...portions of southern California

Concerning...Heavy rainfall...Flash flooding possible

Valid 011520Z - 012120Z

Summary...Deep convection along and ahead of a surface cold front
located about 85 miles west of San Diego will continue to foster a
flash flood risk across the discussion area through 21Z/1p Pacific
Time.

Discussion...Areas of deep convection persist especially in/near terrain-favored upslope regions of the discussion area currently.=20
The convection was being supported by mid-level cooling (which has
fostered a pool of ~250 J/kg SBCAPE over Pacific and near-coastal
regions of the discussion area), orographic ascent (sponsored by
25-30 knot 850mb flow against Transverse and Peninsular coastal
ranges), and 1-1.3 inch PW values - supporting efficient rainfall
processes in/near convective activity. Recent MRMS/observational
data depicts an uptick of rain rates in both Los Angeles Metro
(into the 0.4 inch/hr range) and across San Diego County (where
0.5-0.8 inch/hr rates were estimated). These rain rates were
occuring over urban areas and near sensitive terrain from prior
flash flood impacts, burn scars, and terrain. Flash flooding
remains possible in these areas in the short term.

Models/observations suggest that the aforementioned Pacific cold
front will traverse the region from west to east and bring a
substantial decrease in flood/flash flood potential over time.=20
For the Los Angeles area and Transverse Ranges, this risk will
likely extend into the 18-20Z timeframe before decreasing some.=20
The front will take a bit longer to cross San Diego and adjacent
Peninsular Ranges (around 21Z or so). Flash flooding will remain
possible through the aforementioned timeframes.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6E_IiCTFWyRPvFYk288JNEQ4usNjEugJcYFb_BEOQMvQUtQtZ-envxiDu0hzGaAhh2h-= leCiEekM3pcilfnc8-zSexU$ for graphic product...

ATTN...WFO...HNX...LOX...PSR...SGX...VEF...

ATTN...RFC...RSA...NWC...

LAT...LON 35241857 35091802 34771717 34251662 33621619=20
32831597 32531613 32461695 32551746 33081815=20
33981872 34691879=20

=3D =3D =3D
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AWUS01 KWNH 030901
FFGMPD
CAZ000-031800-

Mesoscale Precipitation Discussion 0003
NWS Weather Prediction Center College Park MD
400 AM EST Sat Jan 03 2026

Areas affected...The Western Transverse Ranges of Southern
California

Concerning...Heavy rainfall...Flash flooding likely

Valid 030900Z - 031800Z

SUMMARY...Flash flooding is likely across the Western Transverse
Ranges this morning as rainfall rates to 1 inch/hour lead to flash
flooding and landslides, especially around burn scars.

DISCUSSION...A highly dynamic weather pattern has set up across
portions of California. A deep upper level low and associated
upper level shortwave are approaching the West Coast. The
shortwave is tapping into a moisture plume set up off the coast of
Mexico and advecting some deeper tropical moisture towards the
coast. PWATs will be increasing to over 1 inch, which is 2.5 sigma
above normal for this time of year. Thus, as a series of surface
fronts (not shown) approach, the addition of upper level energy
from the shortwave and abnormal moisture will allow for rainfall
rates to increase to up to 1 inch per hour into the western
Transverse Ranges this morning.

850 mb southerly flow of 20-30 kts will support increasing upslope
enhancement of the rainfall, which will support the heavier
rainfall locally from Lompoc east through Oxnard, including Santa
Barbara. NASA Sport imagery shows soils are above the 90th
percentile compared to climatology across the area. Thus, a brief
period of heavier rain rates, expected later this morning, should
be all that is needed to fully saturate the soils. Additional
rainfall from there will quickly convert to runoff. This runoff
will fill small streams and creeks, as well as increase the
potential for landslides. Downstream flash flooding, particularly
below the numerous burn scars in the area, is likely through this
morning. The area of heavy rainfall, while progressive, will still
be slow to track eastward down the coast. Any one area should see
anywhere from 3 to 6 hours of rain, heavy at times, before the
plume moves off to the east.

The latest CAMs guidance suggests that by the time the area of
heavy rain arrives into the heart of the Los Angeles basin this
afternoon, it should both be weakening and narrowing. Thus, while
Los Angeles is expected to pick up some rain later this afternoon,
rainfall rates are not expected to be quite as heavy, so impacts
should be somewhat limited.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-sz0p95xYO4NyQz7eawzmC7FC3Xcj-GxL5rzwc8o3o2CAHu5PvVWlLlY6cl-vNBdB_cr= QJlP1sRs0SX0ITy5ulgmzI4$ for graphic product...

ATTN...WFO...LOX...

ATTN...RFC...RSA...NWC...

LAT...LON 35572092 35572058 35572025 35462016 35311989=20
35091962 34861946 34751915 34641845 34521835=20
34121866 34001899 34161953 34392077 35432121=20
35492116=20

=3D =3D =3D
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AWUS01 KWNH 031752
FFGMPD
CAZ000-040200-

Mesoscale Precipitation Discussion 0004
NWS Weather Prediction Center College Park MD
1251 PM EST Sat Jan 03 2026

Areas affected...Southern CA

Concerning...Heavy rainfall...Flash flooding likely

Valid 031750Z - 040200Z

SUMMARY...Excessive Rainfall rates around 1"/hr will likely lead
to additional flash flooding along the Coastal Range and Topatopa
Mountains today where soils are sensitive due to recent heavy
rainfall. Burn scars in the area are also prone to flash flooding
and debris flows. Localized urban-induced flash flooding may occur
in the suburbs north and west of Los Angeles

DISCUSSION...Doppler Radar shows a narrow band of
moderate-to-heavy rain oriented SW-to-NE over the Santa Ynez and
San Rafael Mountains. A narrow squall line ahead of the cold front
is also analyzed just west of Santa Barbara where a couple rain
gauges southeast of Solvang have reported ~1"/hr rainfall totals.
Aside from the squall, most 1-hour rainfall observations show

0.5" totals as the band of heavy rain marches east towards Santa

Barbara. Some 3-hr totals have reached 1.75", which also coincides
with 1-hr averaged rainfall rates just over 0.5". This ribbon of
rainfall is embedded just ahead of an approaching cold front with
the warm sector approaching the Santa Barbara Channel. As the warm
front collides with the western Transverse Ranges, a sliver of
100-250 J/kg of MUCAPE will become available within a highly
saturated atmosphere. Latest RAP forecast soundings near Oxnard
show PWATs approaching 1.25" (above the 97.5 climatological
percentile) and a fully saturated warm-cloud layer that is 9,000ft
deep. Latest 12Z HREF probabilistic guidance does show moderate
chances (40-60%) for 6-hour rainfall totals >3" over the Topatopa
Mountains in Ventura County with similar probabilities along the
Santa Ynez just north of Santa Barbara.

As the frontal system moves east, so will the shield of heavy
rainfall as it heads for the L.A. metro area. However, PWATs
approaching 1.25" will retreat over off the coast and 850mb winds
south of L.A. will tend to be weaker than the >30kt winds farther
west. Therefore, rainfall rates should struggle to get much higher
than 0.5"/hr except for the mountain ranges to the north and west
where upslope enhancement will play a big role. In terms of
impacts, the Santa Ynez, San Rafael, and Topatopa are of greatest
concern given their lingering high soil moisture content (>95th
soil moisture percentile in sfc-100 cm layer) and burn scars in
these ranges. Debris flows and rock slides cannot be ruled out,
particularly within burn scars. As for the urbanized communities,
recent heavy rainfall has made soils sensitive and the greater
concentration in hydrophobic surfaces naturally provides some
flash flood concerns. Given the decreasing rates this afternoon,
however, any flash flooding would generally be ponding on roads
that could pose a hydroplane threat for motorists. In summary, the
mountains north and west of L.A. are likely to witness additional
flash flooding today, although localized flash flooding in more
urbanized settings north and west of L.A. cannot be fully ruled
out.

Mullinax

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-7HaO-2_1JAsI4qeaTRyryPz2LAxCyYFSoB0xzT6DK0BMumMO9tgiqjxmTRaGq3lfeD3= Kt9uO69SZ7BkF6l3r30Lzy4$ for graphic product...

ATTN...WFO...LOX...

ATTN...RFC...RSA...NWC...

LAT...LON 35201980 34861950 34741920 34761878 34731841=20
34471830 34191839 33971867 34151933 34281964=20
34331992 34402043 34712047 35142022=20

=3D =3D =3D
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AWUS01 KWNH 042035
FFGMPD
CAZ000-050400-

Mesoscale Precipitation Discussion 0005
NWS Weather Prediction Center College Park MD
334 PM EST Sun Jan 04 2026

Areas affected...Southern CA Coastal Mountains

Concerning...Heavy rainfall...Flash flooding possible

Valid 042030Z - 050400Z

SUMMARY...Narrow squall of heavy rain and embedded thunderstorms
may produce rainfall rates up to 1"/hr. Given the highly saturated
and sensitive soils along the Coastal Range and Santa Ynez
mountains, flash flooding and mudslides are possible again this
afternoon.

DISCUSSION...Doppler Radar showed a potent squall line approaching
Vandenberg AFB at 20Z moving east ahead of a weakening cold front.
Compared to yesterday, PWATs are generally topping out between
0.9-1.0" within the squall, a little less than yesterday. However,
these values are still above the 90th climatological percentile
and RAP mesoanalysis also shows the southern CA coast has >250
J/kg of MUCAPE at these storms disposal. In addition, these
squalls have upper-level support as the are located beneath the
right-entrance region of a 120kt 250mb jet streak located over the
central Sierra Nevada. Lastly, 925-700mb winds remain out of the
SW and generally between 20-30kts, which is just strong enough and
oriented favorably enough to support some upslope enhancement into
the Coastal Range and Santa Ynez. With anomalous moisture,
sufficient instability, beneficial synoptic-scale ascent, and
topographic enhancement, these storms are likely to produce
locally heavy rainfall as they move east.

The soil sensitivities in the region have only grown worse since
yesterday. MRMS CREST soil saturation over southern Santa Barbara
County is over 85% and most locations within the highlighted
at-risk area are over 50%. A recent FFW near Ventura referenced an
LSR that mentioned more issues along highway 101 with one vehicle
stuck in mud. That band of rainfall produced roughly 1.3" in under
3 hours near Red Mountain and prompted flash flooding/mudslide
issues. This approaching squall is more potent, however it is also
progressive, which should help limit the extent of the flash flood
potential. That said, the recent FFW near Ventura captures the
most notable concern-- soils and burn scars in the area are highly
sensitive and even hourly rates of 0.50-0.75" in an hour could
prompt flash flooding and mud slides in the Santa Ynez. Expect
rainfall totals to surpass 1" in the mountains which could be
enough to trigger more flash flooding in southern Santa Barbara
county this afternoon. Given the lingering instability and forcing
aloft, additional cells could flare up over the Santa Barbara
channel this afternoon and pose a flash flood threat into this
evening.

Mullinax

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5Qm--u4W-pSVK6xYxIwpTyDdgOjKxMsGhyoJ2zRpUOLE5MDP6Vdh9MaSfyAvfcYSvvwp= xwMHw3UfdSvE1h9YTlIJdRg$ for graphic product...

ATTN...WFO...LOX...

ATTN...RFC...RSA...NWC...

LAT...LON 35682058 35402035 35091995 34881962 34761913=20
34721859 34521867 34291923 34271965 34241980=20
34311997 34412060 34552073 34962083 35222099=20
35542098=20

=3D =3D =3D
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AWUS01 KWNH 051856
FFGMPD
CAZ000-060400-

Mesoscale Precipitation Discussion 0006
NWS Weather Prediction Center College Park MD
156 PM EST Mon Jan 05 2026

Areas affected...north-central CA

Concerning...Heavy rainfall...Flash flooding possible

Valid 051854Z - 060400Z

SUMMARY...Isolated flood/flash flood impacts will be possible
across portions of central to northern CA through the late
evening. Peak hourly rainfall of 0.50 to 0.75 inches and peak
additional total rainfall of 2 to 3 inches (locally higher
possible) can be expected through 06Z.

DISCUSSION...GOES West 6.9 micron imagery showed a mid-level
vorticity max/closed low centered near 36.6N 127.0W at 18Z,
embedded within a larger scale trough axis off of the West Coast.
At the surface, low pressure was located ~70 miles northwest of
Point Arena, with a cold front extending south and southwest. Over
the past few hours bands of moderate to heavy rain have been
observed moving across the northern CA Coastal Ranges with current
radar imagery showing an axis of locally heavy rain oriented SSW
to NNE into the North Bay region of San Francisco. In addition,
infrared imagery showed a band of colder cloud tops just ahead of
the cold front where weak MLCAPE values up to ~250 J/kg were
estimated by short term RAP forecasts and SPC mesoanalysis data.

850-700 mb winds were from the southwest at 30 to 40 kt ahead of
the offshore trough axis into north-central CA with PWAT values
ranging from 0.6 inches within the northern Sacramento Valley to
about 0.9 inches just west of San Francisco Bay. Short term
guidance is in good agreement with the track of the mid-level
vorticity max/closed low slowly advancing toward the CA coast
between Point Arena and San Francisco through about 03Z at which
point stalling and eventual southward translation are forecast.
The effect of these larger scale features will translate at the
surface to a SSW to NNE band of heavy rain advancing eastward
toward the central CA coast with embedded peak hourly rainfall
between 0.5 and 0.75 inches (locally higher possible) through the
afternoon and evening. Hourly rainfall up to about 0.5 inches in
an hour will be likely for the northern Sacramento Valley where
weak MLCAPE values up to 250 J/kg area forecast by the RAP from
about 00Z-04Z.

Recent heavy rainfall has left this region of CA more susceptible
to heavy rainfall compared to normal, and there will be the
typical enhancement of heavy rain impacts in and around the San
Francisco Bay region to contend with. Within areas of higher
terrain, localized landslides/rockslides will be possible and
flooding of creeks, streams, urban areas and other
low-lying/flood-prone locations will remain possible through about
04Z. Beyond 04Z, low level winds are likely to weaken and orient
more parallel to the coastline, diminishing the potential for
flooding impacts across the region.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5yfdRhNsr5-w98AcBLIkgKfg5dwl82xgBx00_2ai_nPnbtaLIKpLyJFPncQgplhC3Gld= GFEcRSBOU4e1ZIqU2XZx8Rg$ for graphic product...

ATTN...WFO...EKA...MTR...STO...

ATTN...RFC...RSA...NWC...

LAT...LON 41122240 41062196 40692174 40362164 39812141=20
39542172 38992204 38132212 37402214 36942223=20
36952281 37572330 38122362 38962364 39842330=20
40422311 40932275=20

=3D =3D =3D
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AWUS01 KWNH 090913
FFGMPD
MSZ000-LAZ000-ARZ000-091501-

Mesoscale Precipitation Discussion 0007
NWS Weather Prediction Center College Park MD
412 AM EST Fri Jan 09 2026

Areas affected...Central Mississippi...Eastern and Northeastern
Louisiana...

Concerning...Heavy rainfall...Flash flooding possible

Valid 090911Z - 091501Z

SUMMARY...Flattening steering flow to support segmented training
corridors across the Lower Mississippi River Valley.=20
Strengthening convergence and modestly unstable and seasonably
moist air should support rain rates to 1.75" and localized streaks
of 2-4" in 1-3hrs. Suggesting localized flash flooding is
possible this morning to start a longer day of repeat
thunderstorms.

DISCUSSION...GOES-E WV suite shows mature/decaying shortwave
rapidly elongating and sliding northeast through the central Great
Lakes with a well defined broadly anticyclonically curved
subtropical jet streak across Texas through KY/TN with a stronger
base of the northern stream synoptic trough well upstream emerging
into the southern High Plains. The strong flow and upper-level
dynamic support has resulted in well above normal moisture flux
across the Mississippi River Valley into the Great Lakes; CIRA LPW
denotes core of higher moisture/theta-E air over the West Gulf is
advancing into the entrance of the eastern US atmospheric river
stream. Surface to 850mb values are nearing 1" and is noted with
surface Tds in the upper 60s to even spots of 70 across the Lower
MS Valley.=20

The overall orientation of the upper-level flow is supporting a
pre-frontal confluence zone across E LA at this time, providing
sufficient deep layer convergence to tap the weakly unstable air.
MLCAPEs are analyzed from 500-1000 J/kg through the Sabine River
Valley into the Delta Region of SE AR and W MS. Flux convergence
of 30-35kts at about 30 degrees of convergence overlaps with the
core of the moisture axis with TPW near 1.7". As such, RADAR
denotes a few clusters of thunderstorms developing across NE LA as
well as further north across NE LA into W MS, the latter deeper
into the more ideal unidirectional flow and may support some
training elements as the overall convective development expands
and intensifies over the next few hours. The strong moisture flux
convergence mainly below 700mb will support rates of 1.75"; and
while the forward speeds will limit any specific core, the
upstream divergence aloft and strength of low level flow
convergence will support back-building and redevelopment upstream
through central LA throughout the morning.

Localized storm outflows may be the key to establishing the most
ideal training profiles, but even 1-2 hours of these rates could
support 2-3" totals and locally higher values to 4" would then
begin to exceed the high (3"/3hrs) FFG values in the area.=20
00z/06z HREF Probability of 3"/3hrs peak around 30% in SW to
central MS. Still even with dormant ground conditions, these
rates/totals will have the greatest potential for flash
flooding/rapid inundation conditions where intersecting urban
centers. In any case, these cells will saturate the upper soil
profiles prior to further convective activity expected throughout
the day and evening. As such, flash flooding is only considered
possible and limited to widely scattered in coverage through the
early morning period.=20=20=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9acKgA_eVUQUbWukkTDJ3cwSbuwKek4CYWoR60Ef7vNo7XSoV4CCLFqlziyioqp90ODj= KtIhNIYw04qxDKJ-RKVXHog$ for graphic product...

ATTN...WFO...JAN...LCH...LIX...MEG...SHV...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34138908 34058839 33498829 32868864 32288915=20
31568980 30709050 30919161 30929254 31469279=20
32169248 33289103 33719020=20

=3D =3D =3D
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AWUS01 KWNH 091516
FFGMPD
ALZ000-MSZ000-LAZ000-092000-

Mesoscale Precipitation Discussion 0008
NWS Weather Prediction Center College Park MD
1015 AM EST Fri Jan 09 2026

Areas affected...southeastern LA, southern MS, western AL

Concerning...Heavy rainfall...Flash flooding likely

Valid 091514Z - 092000Z

SUMMARY...Peak rain rates of 2 to 3 in/hr are expected to produce
at least Isolated flash flooding from northern portions of
southeastern LA into southern MS and parts of western AL through
20Z. 6-hr rainfall of 3 to 5 inches will be possible, through
these higher end totals should remain rather isolated should they
materialize.

DISCUSSION...Radar imagery from 15Z showed a axis of heavy rain
oriented ENE from the LA/MS border across the I-55 corridor into
south-central MS and portions of western AL. This axis was located
within an area of pre-frontal low level convergence, augmented by
rain-cooled outflow that extended from near Baton Rouge, LA to
Hattiesburg, MS to Thomasville, AL. 925 mb winds of 25-35 kt were
observed over southeastern LA into southern MS, converging along
this axis which was oriented parallel to the mean steering flow,
supporting training. Hourly rainfall near and just over 2 inches
has been observed near the LA/MS border within the past 2 hours
where MLCAPE of 500-1000 J/kg and PWATs of 1.7 to 1.8 inches were representative of the environment, reported on the 12Z soundings
from LIX and JAN.

Short term guidance from the RAP shows similar low level flow
continuing over the next few hours with the establishing cold pool
likely serving as a focus for renewed convective development
through 18Z to 19Z from the LA/MS border into southern MS. ENE
steering flow is likely to support cells moving downstream into
western AL while some upstream development occurs back to the WSW.
The environment is capable of supporting hourly rainfall in the
2-3 inch range, although 1 to 2 inches per hour will be more
common. Localized potential for 3 to 5 inches over the next 6
hours will exist with at least localized flash flooding appearing
likely, especially within any urban areas and as high rain rates
overcome dry antecedent conditions.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_TyiPQgtr4G0Ii50gtuvjxeex8vVdO5evYOP54YZtWf02QDLtAIGPEdd-TkMEu8RjjIG= d01F8d6HGazeOuastO5EijM$ for graphic product...

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 32848772 32518711 31988718 31498776 30978897=20
30569019 30009159 30399210 31319161 32108995=20
32618877=20

=3D =3D =3D
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AWUS01 KWNH 092005
FFGMPD
ALZ000-MSZ000-LAZ000-100100-

Mesoscale Precipitation Discussion 0009
NWS Weather Prediction Center College Park MD
304 PM EST Fri Jan 09 2026

Areas affected...south-central LA into south-central MS and
western/central AL

Concerning...Heavy rainfall...Flash flooding likely

Valid 092003Z - 100100Z

SUMMARY...Relatively narrow axes (or a single axis) of heavy rain
appear likely to maintain an increased flash flood potential into
the early evening from south-central LA into south-central MS and western/central AL. 2 to 4 inches and areas of flash flooding will
be likely within portions of this corridor with locally higher
rain totals possible.

DISCUSSION...Radar imagery from 1945Z showed a persistent axis of
moderate to heavy rain from near the southeastern LA/MS border
into south-central MS and western AL which has been in roughly the
same location over the past 3-4 hours. Embedded hourly rainfall
has been observed in the 1-2 inch range at times and roughly 2 to
4 inches have fallen from near Baton Rouge into south-central MS
as far east as Waynesboro, MS since early this morning. A
combination of rain-cooled outflow and a slightly elevated axis of
convergence located within 925-850 mb layer have helped to focus
these areas of heavy rain over the past few hours where MLCAPE has
increased into the 500-1500 J/kg range from the southern MS/AL
border toward Lake Pontchartrain (via SPC mesoanalysis data).
Additional rainfall was occurring farther north in AL along the
elevated convergence axis where 2 to 3 inches was reported over
the past 6 hours, but a lack of instability has tempered rainfall
rates across northern locations. Radar imagery also showed
additional thunderstorms building over the I-10 corridor of
south-central LA, rooted near the surface within weaker/more
subtle axes of near surface convergence.

RAP forecast guidance suggests an inflection point along the
convergence axis (currently over the south-central MS/AL border)
will advance northeastward in the short term while the axis of
convergence to its west lifts slightly north. Meanwhile, the WSW
to ENE oriented outflow boundary in place over south-central MS is
likely to continue to serve as a focus for additional thunderstorm
development. Therefore, expectations are for continued
thunderstorms over the region through early evening, initiating
along and just north of the surface outflow and farther north on
elevated convergence with training via mean movement off toward
the ENE. Embedded short term training may also occur with the
thunderstorms moving northward through south-central LA.

Hourly rainfall of 1 to 2 inches, but localized hourly rainfall in
excess of 2 inches is expected through early evening from southern
portions of the Lower Mississippi Valley into western/central AL.
The better instability is forecast to remain situated west of the
MS/AL border but pockets of locally higher instability into
portions of AL may also support flash flooding to the east as
well. Given dry antecedent conditions leading up to this event,
flash flooding potential will be greatest over urban areas and
where heavy rain has fallen over the past 12 hours.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9m4qxItj-dnwomeDGXhQp86jHguqhmSXSAAR6bEQjaMBomi8lsV-t-Am1_0oAWUcpSxH= eCihXcSKifpS29MX2Hrx8sk$ for graphic product...

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 33568684 33488628 33168594 32648596 32198649=20
31858711 31258872 30868957 30379076 30359177=20
30639220 31179203 31969105 32449012 32698924=20
33208778=20

=3D =3D =3D
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AWUS01 KWNH 100147
FFGMPD
ALZ000-MSZ000-LAZ000-100545-

Mesoscale Precipitation Discussion 0010
NWS Weather Prediction Center College Park MD
846 PM EST Fri Jan 09 2026

Areas affected...Parts of Southern MS into western-central AL

Concerning...Heavy rainfall...Flash flooding possible

Valid 100145Z - 100545Z

SUMMARY...A relatively narrow corridor of cell training will
maintain the potential for isolated areas of flash flooding
through the remainder of the evening. Additional rainfall totals
of 2 to 3 inches are expected across many locales within this
corridor through midnight CST, though isolated amounts of 4-5
inches areas are expected.

DISCUSSION...Latest GOES-E longwave IR imagery showed a well
developed, rather expansive west-to-east Warm Conveyor Belt (WCB)
of higher/colder cloud tops from northern Mexico northeast through
eastern TX and into the Mid-South and TN Valley. Robust upper
trough over the southern Rockies-High Plains and attendant upper
level jet streak on the eastern flank is helping to enhance the
deep-layer forcing and low-level frontogenesis ahead of the
approaching cold front, which will coincide with the boost in the
low-level moisture transport from the Gulf as 850 mb winds
increase to 30-40 kts later this evening.

Meanwhile, a narrow axis of higher deep-layer CAPE (1000-1500+
J/Kg) will also nudge northeastward from the Gulf Coast into
southern MS and southern-central AL, coinciding with PWs climbing
between 1.8 and 2.0" in the expanding pre-frontal convective
environment. Multiple, quasi-linear convective segments will tend
to train within this narrowing corridor of more optimal
instability and available PW. The mesoscale (CAM) guidance has
struggled a bit handling the current setup, compared to the radar
mosaic over the past few hours. Recent HRRR and RRFS runs have
caught up a bit however. High res ensembles (HREF and RRFS)
probabilities of hourly rainfall rates exceeding 1-2" are a bit
lower than reality (especially the 2"/hr probabilities),
indicative that the event may only just now be getting better
handled by the guidance. Much of the CAM guidance show the
heaviest rainfall south of BHM through midnight CST, however with
notably lower FFG over northeast MS and northern AL, it would not
take as much rainfall to cause additional runoff issues,
especially considering what has already fallen.

Hurley

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6j7wsjsHr8ga0tgXnpJ4FOHJWysiSmMEDaIqyT_p8lovh63Ekd-FfvWNITKFWu9QqJ3u= x9ZuW_d7bZj_84atsYa08l0$ for graphic product...

ATTN...WFO...BMX...HUN...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34198699 32868611 31658789 30709029 31699073=20
33308893=20

=3D =3D =3D
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AWUS01 KWNH 100444
FFGMPD
MSZ000-LAZ000-TXZ000-101000-

Mesoscale Precipitation Discussion 0011
NWS Weather Prediction Center College Park MD
1142 PM EST Fri Jan 09 2026

Areas affected...Southeast to East Texas...Western and Northern
Louisiana...

Concerning...Heavy rainfall...Flash flooding possible

Valid 100445Z - 101000Z

SUMMARY...Strengthening scattered to widely scattered
thunderstorms capable of 1.5"/hr and localized 2-3" totals given
some short-duration training potential for flanking cell
development. Greater soil saturation/lower FFG, north and
proximity to Houston metro/urban runoff to south pose localized
possible incident or two for flash flooding through overnight
period.

DISCUSSION...Regional RADAR mosaic and 10.3um IR loop depict a few
stronger thunderstorm clusters extending from near Victoria
northeastward across Southeast TX toward a weak surface low near
KOCH. East of the low, a west to east stationary front crosses
near I-20 and recently saturated upper soil profiles given broad
1-2" totals throughout the day. Surface to boundary layer
southerly flow continues to advect upper 60s/low 70s Tds with
modestly unstable air mass in the warm sector with MLCAPE values
remaining at or above 1000 J/kg with spots of 2000 J/kg near the
Upper TX coast. Upper level jet streak continues to expand and
strengthen across the Ozark Plateau though broad right entrance
ascent is providing strong divergence aloft and supporting the
slightly backed and 20-25kts of low-level jet flow to obliquely
intersect the slowly eastward advancing cold front.=20

While mid to upper levels remain dry, the anomalous moisture
remains though 700mb with over 1.5" and spots nearing 1.75" within
the warm sector. This results in solid moisture flux convergence
and solid instability to maintain/expand the convective coverage
though likely still in a scattered nature over the next few hours.
Flux convergence is supporting moderately efficient rainfall
production with 1.5-1.75"/hr rates. Forward progression will
continue to be a limiting factor toward 2-3" streaks of rainfall
totals across the area of concern, especially as the core of the
jet (and therefore the right entrance divergence) shift
northeastward and direct circulation allows for faster progression
of the cold front through the TX Coastal Plain.=20

Overall totals are not a tremendous concern across the Coastal
Plain, with a solid exception of the hydrophobic urban/suburban
corridor of Houston. The sheer rates would be the greatest
potential and even slight probability of localized 2"/hr rates may
be sufficient to result in localized flooding concerns. Further
north across the northern Piney Woods of E TX into Northern LA,
the recent rainfall will locally result in above normal runoff,
and compromised FFG values of less than 2"/hr and 3"/3hr remain
capable of being exceeded again. As such, a few incidents of
localized flash flooding will remain possible through the
overnight period as the front presses through from west to east.=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5e45rP2JunIuVcPEhh0jU35Epu8JkIn1Nkw9iyBplNfFJrna5KVV_1R27PiPw8ZbzmRa= 2_o7E4DnM3kcR0t4xyG5GNM$ for graphic product...

ATTN...WFO...HGX...JAN...LCH...SHV...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON 32959190 32879118 32299104 31379165 30549283=20
29959426 29399553 29649617 30229584 30649558=20
31419478 32189422 32789339 32919271=20

=3D =3D =3D
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AWUS01 KWNH 100536
FFGMPD
GAZ000-ALZ000-MSZ000-101100-

Mesoscale Precipitation Discussion 0012
NWS Weather Prediction Center College Park MD
1236 AM EST Sat Jan 10 2026

Areas affected...Southeast MS...Central AL...Northwestern GA...

Concerning...Heavy rainfall...Flash flooding possible

Valid 100535Z - 101100Z

SUMMARY...Rainfall intensity is reducing though there remains a
continued favorable training environment and persistent warm air
advection for additional upstream development to maintain training
through the overnight period. Already wetted/saturated soils
with additional 2-3" may result in localized possible flash
flooding.

DISCUSSION...04z Surface analysis depicts main synoptic front
bisects Middle TN into eastern MS before it starts to bend back
westward across central MS to near Vicksburg and along I-20 under
the influence of the upstream DPVA from the shearing upper level
trough and strong 130kt+ jet over the Ozark Plateau. Still, the
influence of the initial shortwave and atmospheric river/stream
out of the western Gulf yesterday continues to slide northeastward
across central AL toward the Southern Appalachians later this
morning. VWP shows broad 25-40kt LLJ from SE LA across AL into
western GA; which aligns with the core of enhanced moisture per
CIRA LPW sfc-850 and 850-700mb layers with .75-.9" and .4-.5" in
each layer respectively. RAP analysis and GPS network confirm
1.75" core in central AL sliding northward.

The flow through this layer remains strong and nearly
unidirectional from 850 upward to support a narrow training
profile for ongoing/weakening convection and anything that would
redevelop upstream. The surface to boundary layer does still have
some additional southerly component and surface
analysis/instability axis denotes an effective rain-cooled
isentropic ascent plain/front extending from the main front near
Vicksburg to Jackson to south of Meridian to near Montgomery. As
such mildly unstable air with 500-1000 J/kg of MUCAPE south of the
boundary will isentropically ascend to provide some scattered
thunderstorm activity upstream. This should help to maintain some
training profile across central AL with occasional 1.5-1.75"/hr
rates and localized 2-3" streaks, eventually extending toward W GA
with slowly diminishing rates and therefore totals.

However, given the prolonged nature, short term FFG values may not
be exceeded except for areas already compromised across Southeast
MS and far SW AL and urban centers along the way. However, add
this 1-3" totals to the 1-2" totals already fallen across AL into
GA and longer term exceedance is possible, suggesting localized
flash flooding conditions remain possible through the overnight
period into early morning.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!435-j2SzxdSRBUw-cE0OMsONPir6gcMUx4lDPm-ZmspqOtZkTROIgK4FzQEfJoUP2Gal= mFisCP7jRcMnc0sYzE9_uBw$ for graphic product...

ATTN...WFO...BMX...FFC...JAN...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34408506 34308429 33678411 33238444 32488549=20
31648728 31158841 31198950 31919077 32649045=20
33158827 33538722 34128572=20

=3D =3D =3D
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AWUS01 KWNH 100830
FFGMPD
ALZ000-MSZ000-LAZ000-101330-

Mesoscale Precipitation Discussion 0013
NWS Weather Prediction Center College Park MD
329 AM EST Sat Jan 10 2026

Areas affected...Eastern Louisiana...Southern Mississippi

Concerning...Heavy rainfall...Flash flooding possible

Valid 100830Z - 101330Z

SUMMARY...Pre-frontal confluence band activating within narrow
remaining instability axis in proximity to moisture axis enough to
support 1.75-2"/hr rates. Cell motions support some short-term
repeating though already saturated/flooded areas. As such,
localized flash flooding is likely to occur again through early
morning.

DISCUSSION...GOES-E 10.3um and Regional RADAR depict an area of
increasing convective development along a low level confluence
line extending from near Marsh Island across Baton Rouge, LA
toward McComb MS before intersecting with a broader west to east
rainfall reinforced outflow or effective isentropic boundary. RAP
analysis depicts a narrow instability axis with 1500-1750 J/kg of
MLCAPE and generally aligns with the western edge of slightly
higher low level moisture where Tds climb above 70 a few degrees.=20
VWP also note an increase in low level wind speeds toward 40+kts
and remain fairly unidirectional through 500mb well ahead of the
frontal zone. As such, there remains a favorable training
orientation for the convection. SPC MCD 18 alludes to favorable
shear environment for some rotating cells as well, further
increasingly moisture flux convergence allowing for rates to reach
1.75-2"/hr potentially. Upstream cold front is starting to press
eastward, but there remains a few hours of potential training of
these cells. This matches most closely to the 00z ARW solution as
well as recent RAP runs though other rapid refresh guidance
provides some increased confidence to this evolution.

Unfortunately, the orientation appears to intersect locations that
had received over 4" yesterday afternoon. This has resulted in
compromised FFG values below 2"/hr for solid portion of the MPD
area of concern and with 1-2 hours of training spots of additional
2-3" are probable and would likely result in localized flash
flooding to occur once again across far northern East Louisiana
into Southern MS. Combine this with any remaining convective
cells along the cold front passing through by 14-15z, consider the
potential for flash flooding to once again be likely across this
area into the early morning hours.=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4aacJg2RqFJ5V8-2vwdZ2lKcSM8fYZxP72KCyyCnUC5vlx1yoCazj4zpzWsinq-zZNFh= viusEplqvv9jnVIymFAi_pU$ for graphic product...

ATTN...WFO...BMX...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 33058867 32998809 32558766 31878777 31448828=20
31178870 30878924 30549032 30359117 30689162=20
31319135 31909091 32838963=20

=3D =3D =3D
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AWUS01 KWNH 100834
FFGMPD
ALZ000-MSZ000-LAZ000-101330-

Mesoscale Precipitation Discussion 0013...Corrected
NWS Weather Prediction Center College Park MD
334 AM EST Sat Jan 10 2026

Corrected for Concerning line: Flash Flooding Likely

Areas affected...Eastern Louisiana...Southern Mississippi

Concerning...Heavy rainfall...Flash flooding likely

Valid 100830Z - 101330Z

SUMMARY...Pre-frontal confluence band activating within narrow
remaining instability axis in proximity to moisture axis enough to
support 1.75-2"/hr rates. Cell motions support some short-term
repeating though already saturated/flooded areas. As such,
localized flash flooding is likely to occur again through early
morning.

DISCUSSION...GOES-E 10.3um and Regional RADAR depict an area of
increasing convective development along a low level confluence
line extending from near Marsh Island across Baton Rouge, LA
toward McComb MS before intersecting with a broader west to east
rainfall reinforced outflow or effective isentropic boundary. RAP
analysis depicts a narrow instability axis with 1500-1750 J/kg of
MLCAPE and generally aligns with the western edge of slightly
higher low level moisture where Tds climb above 70 a few degrees.=20
VWP also note an increase in low level wind speeds toward 40+kts
and remain fairly unidirectional through 500mb well ahead of the
frontal zone. As such, there remains a favorable training
orientation for the convection. SPC MCD 18 alludes to favorable
shear environment for some rotating cells as well, further
increasingly moisture flux convergence allowing for rates to reach
1.75-2"/hr potentially. Upstream cold front is starting to press
eastward, but there remains a few hours of potential training of
these cells. This matches most closely to the 00z ARW solution as
well as recent RAP runs though other rapid refresh guidance
provides some increased confidence to this evolution.

Unfortunately, the orientation appears to intersect locations that
had received over 4" yesterday afternoon. This has resulted in
compromised FFG values below 2"/hr for solid portion of the MPD
area of concern and with 1-2 hours of training spots of additional
2-3" are probable and would likely result in localized flash
flooding to occur once again across far northern East Louisiana
into Southern MS. Combine this with any remaining convective
cells along the cold front passing through by 14-15z, consider the
potential for flash flooding to once again be likely across this
area into the early morning hours.=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8A94cu_2EwIsReGlPc-3vX9yAGxP4uM-DkHqQ9QnUZE7dddVxb0_aR_v2XJ7MMiUV3RH= ZqruWZkdv7CYjxwdXzJPM8o$ for graphic product...

ATTN...WFO...BMX...JAN...LIX...MOB...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 33058867 32998809 32558766 31878777 31448828=20
31178870 30878924 30549032 30359117 30689162=20
31319135 31909091 32838963=20

=3D =3D =3D
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AWUS01 KWNH 101355
FFGMPD
FLZ000-GAZ000-ALZ000-MSZ000-LAZ000-101954-

Mesoscale Precipitation Discussion 0014
NWS Weather Prediction Center College Park MD
855 AM EST Sat Jan 10 2026

Areas affected...portions of southeastern Louisiana, southern
Mississippi, and southern/central Alabama

Concerning...Heavy rainfall...Flash flooding likely

Valid 101354Z - 101954Z

Summary...Flash flood potential continues across southern
Mississippi this morning. This threat will shift eastward while
gradually becoming more isolated through 19Z/1p Central.

Discussion...Recent radar mosaic imagery depicts an extensive,
linear convective complex extending from near Gadsden, AL through
Birmingham, AL and southwestward to near Hammond, LA. Convection
has trended toward more forward propagation over the past several
hours, but remain capable of 1-2 inch/hr rain rates - especially
across southern Mississippi and southeastern Louisiana where
forward motions are slower (around 20-30 knots) and quality
pre-convective moisture exists. The storms are in an environment
characterized by moderate surface-based buoyancy (around 1000-1500
J/kg - highest from central Alabama through the New Orleans area)
and 1.4-1.6 inch PW values - both characteristic of typical
profiles supporting deep moist convection and heavy rainfall
rates. Additionally, some of the activity was falling on areas of
southern Mississippi that have received 5-8 inches of rainfall
over the past 24 hours (particularly near Hattiesburg, Waynesboro,
MS and surrounding areas). FFGs are near zero in those areas,
supporting an imminent and ongoing flash flood threat there.=20
Farther northeast and southeast of the Hattiesburg area, FFGs are
a bit higher (around 1 inch/hr in Alabama - closer to 2-3
inches/hr in Louisiana), suggestive of more scattered flash flood
potential in those area in the short term.

The forward-propagating nature of this complex will result in
storms gradually moving out of the most sensitive, water-logged
areas of the discussion area through the morning and early
afternoon. The downstream airmass is still supportive of
occasional areas of 1-1.5 inch/hr rain rates, promoting flash
flood potential especially in urban and sensitive areas of the
discussion area. Flash flooding remains most likely in
southeastern Mississippi this morning, with a lesser-concentrated
risk throughout the remainder of the discussion area.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7OGoiGqj85_Vesa1ojoKLDKhAaPxWV1B9qkkhqgPTdSo7FDat7FsdJY3lqM0RO53_it5= 34zevUAZFeSLoq2RL78HvGc$ for graphic product...

ATTN...WFO...BMX...FFC...JAN...LCH...LIX...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34318457 33968412 32578415 31058531 30358760=20
29228947 29239063 29609114 31409039 32788822=20
34228567=20

=3D =3D =3D
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AWUS01 KWNH 101410
FFGMPD
FLZ000-GAZ000-ALZ000-MSZ000-LAZ000-101954-

Mesoscale Precipitation Discussion 0014
NWS Weather Prediction Center College Park MD
909 AM EST Sat Jan 10 2026

Areas affected...portions of southeastern Louisiana, southern
Mississippi, southern/central Alabama, and western/northern
Georgia

Concerning...Heavy rainfall...Flash flooding likely

Valid 101354Z - 101954Z

Summary...Flash flood potential continues across southern
Mississippi this morning. This threat will shift eastward while
gradually becoming more isolated through 19Z/1p Central.

Discussion...Recent radar mosaic imagery depicts an extensive,
linear convective complex extending from near Gadsden, AL through
Birmingham, AL and southwestward to near Hammond, LA. Convection
has trended toward more forward propagation over the past several
hours, but remain capable of 1-2 inch/hr rain rates - especially
across southern Mississippi and southeastern Louisiana where
forward motions are slower (around 20-30 knots) and quality
pre-convective moisture exists. The storms are in an environment
characterized by moderate surface-based buoyancy (around 1000-1500
J/kg - highest from central Alabama through the New Orleans area)
and 1.4-1.6 inch PW values - both characteristic of typical
profiles supporting deep moist convection and heavy rainfall
rates. Additionally, some of the activity was falling on areas of
southern Mississippi that have received 5-8 inches of rainfall
over the past 24 hours (particularly near Hattiesburg, Waynesboro,
MS and surrounding areas). FFGs are near zero in those areas,
supporting an imminent and ongoing flash flood threat there.=20
Farther northeast and southeast of the Hattiesburg area, FFGs are
a bit higher (around 1 inch/hr in Alabama - closer to 2-3
inches/hr in Louisiana), suggestive of more scattered flash flood
potential in those area in the short term.

The forward-propagating nature of this complex will result in
storms gradually moving out of the most sensitive, water-logged
areas of the discussion area through the morning and early
afternoon. The downstream airmass is still supportive of
occasional areas of 1-1.5 inch/hr rain rates, promoting flash
flood potential especially in urban and sensitive areas of the
discussion area. Flash flooding remains most likely in
southeastern Mississippi this morning, with a lesser-concentrated
risk throughout the remainder of the discussion area.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8Hlcy_JkIVC_spif7StIjfVMqKja9sq8Gg9rt_MmTn0QKzEocsUt4og8AxJVfmfAPSGm= Rp1xHZW4-kpUSY8JUQ28y5o$ for graphic product...

ATTN...WFO...BMX...FFC...JAN...LCH...LIX...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34318457 33968412 32578415 31058531 30358760=20
29228947 29239063 29609114 31409039 32788822=20
34228567=20

=3D =3D =3D
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