ACUS48 KWNS 020940
SWOD48
SPC AC 020939

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0339 AM CST Fri Jan 02 2026

Valid 051200Z - 101200Z

...DISCUSSION...
Convective potential appears likely to increase across at least the South-Central States, centered on eastern TX to the Lower MS Valley
mid to late week. While day-to-day predictability is low, the
broader signal hints at potentially multiple days of at least
low-probability severe during D6-9/Wednesday-Saturday.

Initial concern is with the downstream evolution of a lower-latitude
shortwave trough across Baja CA and northwest Mexico early in the
week. Guidance continues to struggle with spatiotemporal aspects of
this wave by mid-week. But potential exists for this wave to
interact with a modifying warm-moist sector from the western Gulf
into the South-Central States. Faster guidance indicates
severe-storm potential may commence by late Wednesday.

In the wake of the initial shortwave trough, guidance consensus
suggests that a broad upper trough should evolve across the West
late week. This may yield an expansive swath of fast mid-level
southwesterlies from the southern High Plains to the Northeast.
Given a lack of frontal intrusion into the northwest Gulf with the
lead wave, seasonably rich low-level moisture may overlap a portion
of this fast flow regime around Friday-Saturday. Latest NSSL GEFS ML
V1.2 probs appear reasonable with depictions of 5 percent peak probs
on D6-7, followed by 10 percent areas on D8-9.

..Grams.. 01/02/2026

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ACUS48 KWNS 030932
SWOD48
SPC AC 030931

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CST Sat Jan 03 2026

Valid 061200Z - 111200Z

...DISCUSSION...
Convective potential appears likely to increase across at least the South-Central States by late week. Guidance spread remains large
with the handling of a lower-latitude shortwave trough that will
initially be off the southern CA/Baja CA coast on D4/Tuesday.
Non-ECMWF deterministic guidance largely eject this wave quickly east-northeastward into the southern Great Plains by late
D5/Wednesday night. The ECMWF, EC-AIFS, and AIGFS maintain a slower
and more reasonable scenario of progression through D6/Thursday.
This will probably interact with a modifying warm-moist sector from
the western Gulf, with some severe potential in a portion of the
South-Central States. Spatiotemporal detail differences exist even
among the preferred slower guidance and the majority of GEFS/ECENS
ML probs remain below 15 percent for Thursday.

For the broad upper trough over the West, latest EC-AIFS and the
ECMWF now depict potential of a negative-tilt evolution compared to
prior runs and other guidance. Spread is quite large within the
ECENS for both the AI/non-AI, indicative of a poorly predictable
pattern for shortwave impulses embedded within the broader trough.
But with potential for fast mid-level southwesterlies overlapping
seasonably rich low-level moisture emanating north from the western
Gulf, and some scenarios indicative of cyclogenesis over the central
states, a severe area highlight may eventually be warranted on
D7/Friday.

..Grams.. 01/03/2026

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ACUS48 KWNS 040932
SWOD48
SPC AC 040931

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CST Sun Jan 04 2026

Valid 071200Z - 121200Z

...DISCUSSION...
A low-latitude closed low west of Baja CA at 12Z Wednesday should
evolve back into an open wave, aided by the development of a
large-scale trough becoming established over the West. EC-AIFS and
AIGFS remain the preferred guidance for a more probable slower
ejection of the low-latitude wave onto the southern Great Plains
through Thursday. At least isolated severe potential seems plausible
to the east-southeast of a southern High Plains lee cyclone as a
modifying warm-moist sector advects north from the western Gulf. But yesterday's NCAR ECENS-based ML guidance remains below 5 percent for
Thursday, while the latest GEFS-based SPC-CSU and NSSL ML guidance
have trended lower to only 5 percent peak areas.

D6/Friday still appears to have the best relative severe potential,
despite the pair of GEFS-based ML guidance trending lower and in
areal extent of 5 percent peak probs. Neither of these have any
appreciable overlap with the preferred ECENS-based 5 percent areas
from NCAR. In any case, an amplified upper trough appears likely to
shift from around the Rockies to the Great Plains. Most EC-AIFS ENS
members now support central states cyclogenesis. But predictability
remains low regarding the spatiotemporal details and amplitude of
cyclogenesis, which is likely related to the handling of shortwave
impulses embedded within the broader trough. An area-of-interest for
a future 15 percent severe highlight roughly includes the Lower MS
to TN Valleys and Deep South.

..Grams.. 01/04/2026

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ACUS48 KWNS 050951
SWOD48
SPC AC 050949

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0349 AM CST Mon Jan 05 2026

Valid 081200Z - 131200Z

...DISCUSSION...
The noticeable model differences on D3/Wednesday in the evolution of
a low-latitude shortwave impulse, ejecting ahead of an amplifying
upper trough over the West, persist into D4/Thursday. This renders
low confidence in a greater than low-probability severe risk on
Thursday, which appears roughly centered on the Ark-La-Tex to
Mid-South.

Peak severe potential still appears centered on D5/Friday.
Predictability remains sub-optimal with the basal portion of the
amplified upper trough from the Southwest. This renders large spread
across guidance in timing and amplitude of downstream cyclogenesis
from the south-central Great Plains towards the Great Lakes,
impacting the breadth of severe potential. However, with preceding
days of airmass modification from the western Gulf, a pronounced
wintertime warm-moist sector should become established towards the
Lower OH Valley vicinity. This should be coincident with a broad
swath of strong southwesterly mid-level flow that should be
strengthening during the period.

The trio of latest NCAR ECENS-based and SPC-CSU GEFS-based ML
probabilities have trended upward again with similarly large 15
percent regions. Meanwhile, the NSSL GEFS-based V1.2 has increased
back to a 10 percent, but displaced farther south. For this
forecast, have opted to include a 15 percent highlight, centered on
the Lower MS to Lower OH Valleys where confidence is greater for a
favorable convective environment on Friday afternoon to night
despite the modest synoptic-scale predictability.

ML probs for D6/Saturday remain low, with only the NCAR_Pangu
highlighting a 5 percent area. But given the aforementioned timing
differences with the evolution of the upper trough/surface
cyclogenesis, very fast deep-layer wind fields could persist atop a
more limited thermodynamic environment. A conditional convective
damaging wind threat seems apparent, with low confidence on spatial extent/amplitude at this time range.

..Grams.. 01/05/2026

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ACUS48 KWNS 061002
SWOD48
SPC AC 061000

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CST Tue Jan 06 2026

Valid 091200Z - 141200Z

...DISCUSSION...
...D4/Friday: Lower MS Valley vicinity...
A mid/upper-level shortwave trough initially over the southern
Rockies is forecast to take on a positive tilt as it moves eastward
on Friday, as a northern-stream shortwave trough digs from the
Canadian Prairies toward the Upper Great Lakes. Some guidance has
trended weaker and farther south with a surface low developing near
the lower MS Valley by Friday evening, though a relatively large
warm sector is still expected to be in place through most of the
period. Scattered to widespread storm development is expected from
parts of east TX into the lower MS Valley, with sufficient
deep-layer shear for organized convection and some attendant severe
threat. Some adjustments to the 15% area have been made, based on
guidance trends regarding surface low placement and the northward
extent of the favorable warm sector.

...D5/Saturday: Parts of the East...
Uncertainty regarding the synoptic pattern increases by D5/Saturday,
with varying solutions regarding the extent of mid/upper-level
trough amplification across the eastern CONUS, and the strength of
the related surface low. Guidance generally agrees that buoyancy
will be limited across much of the warm sector on Saturday. However,
any organized convection that develops Friday night may persist into
Saturday morning across parts of the Southeast, with some potential
for an isolated severe threat. Farther north, the strongest
solutions (such as the 00Z deterministic ECMWF) depict notable
intensification of low/midlevel flow from the Ohio Valley into the
Mid Atlantic, which could result in some damaging-wind potential
with any low-topped convection along or ahead of an advancing cold
front.

..Dean.. 01/06/2026

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ACUS48 KWNS 070917
SWOD48
SPC AC 070915

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0315 AM CST Wed Jan 07 2026

Valid 101200Z - 151200Z

...DISCUSSION...
...D4/Saturday...
Some severe potential remains evident from parts of the Southeast
into the Carolinas, Mid Atlantic, and possibly Ohio Valley on
D4/Saturday, but details remain uncertain.

Guidance generally depicts continued amplification of a deep and
progressive shortwave trough on Saturday across the eastern CONUS. A
deepening surface low is forecast to move from the Ohio Valley
toward the Lower Great Lakes, as a trailing cold front sweeps
through much of the Southeast and Mid Atlantic. Strongly sheared
convection with some severe potential may be ongoing Saturday
morning along/ahead of the cold front, from parts of MS/AL into the
southern Appalachians. Strong deep-layer flow/shear will eventually
overspread parts of the Ohio Valley, Mid Atlantic and Carolinas.
However, longevity and magnitude of the severe threat in these
regions is uncertain, as instability weakens with northeastward
extent, and stronger ascent becomes increasingly displaced north of
the warm sector with time.

...D5/Sunday - D8/Wednesday...
The cold front is forecast to move through coastal NC and the FL
Peninsula on Sunday, but weak ascent and buoyancy are expected to
limit organized storm potential. Dry and stable conditions in the
wake of this cold frontal passage are expected to minimize
severe-storm potential across the CONUS into early next week.

..Dean.. 01/07/2026

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ACUS48 KWNS 080918
SWOD48
SPC AC 080916

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0316 AM CST Thu Jan 08 2026

Valid 111200Z - 161200Z

...DISCUSSION...
Organized severe potential currently appears low through the
extended-range period.

A cold front will move through coastal NC and parts of FL on
D4/Sunday, in advance of a deep upper trough moving across the
eastern CONUS, but ascent and buoyancy within the remaining warm
sector appear too weak to support organized storms. For D5/Monday
through D8/Thursday, generally dry and stable conditions in the wake
of multiple frontal intrusions will tend to limit thunderstorm
potential across most of the CONUS. Some guidance (notably the 00Z
ECMWF) indicates that thunderstorm chances may return to parts of
the FL Peninsula by mid week, in association with renewed upper
trough amplification across the eastern CONUS. However, with
guidance generally depicting only weak surface wave development
during this time frame, confidence in organized storm development
remains low.

..Dean.. 01/08/2026

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ACUS48 KWNS 090945
SWOD48
SPC AC 090943

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CST Fri Jan 09 2026

Valid 121200Z - 171200Z

...DISCUSSION...
Mid-level northwesterly flow is forecast to become established
across the central U.S. on Monday. This appears likely to persist
into mid-week as a large-scale trough develops in the Mississippi
Valley. The pattern will help to usher cold and dry air southward
into the Great Plains and Southeast, which will limit moisture
return. From Thursday into Friday, the trough is forecast to move
into the eastern U.S., reinforcing northwesterly mid-level flow over
much of the nation. As a result, a cold and dry airmass is expected
to remain over the continental U.S, minimizing the potential for
thunderstorm development.

..Broyles.. 01/09/2026

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ACUS48 KWNS 100941
SWOD48
SPC AC 100940

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0340 AM CST Sat Jan 10 2026

Valid 131200Z - 181200Z

...DISCUSSION...
A large-scale upper-level trough is forecast to develop across the
central and eastern U.S. during the mid-week. This feature is
forecast to move eastward toward the Atlantic Seaboard late in the
week, as another trough takes its place further west across the
Mississippi Valley. In response to the pattern, a large area of high
pressure is forecast to settle into the central U.S. on Wednesday
and move slowly across the Gulf Coast region on Thursday and Friday.
Another large area of high pressure is forecast to move southward
into the western and central U.S. by the weekend. As a result, the
airmass across most of the continental U.S. during the mid to late
week should be cold and relatively dry, suggesting thunderstorm
development will be unlikely during the Day 4 to 8 period.

..Broyles.. 01/10/2026

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ACUS48 KWNS 110947
SWOD48
SPC AC 110946

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CST Sun Jan 11 2026

Valid 141200Z - 191200Z

...DISCUSSION...
A persistent large-scale upper-level trough is forecast to remain in
the eastern U.S. during the Day 4 to 8 period. This pattern will be
favorable for repeated cold air intrusions into the lower
forty-eight states from mid to late week. Cold and dry surface high
pressure will dominate across much of the nation, making conditions
unfavorable for thunderstorm development.

..Broyles.. 01/11/2026

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ACUS48 KWNS 120939
SWOD48
SPC AC 120938

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CST Mon Jan 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...
A persistent large-scale upper-level trough is forecast to remain
over the east-central U.S. during the Day 4 to 8 period. This
pattern will be favorable for repeated cold air intrusions into the
continental U.S late this week into early next week. As a result,
cool and dry conditions are expected to remain in place over much of
the nation, making thunderstorm development unlikely in most areas.
No severe threat is forecast to develop over the continental U.S.
through early next week.

..Broyles.. 01/12/2026

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ACUS48 KWNS 120955
SWOD48
SPC AC 120954

Day 4-8 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0354 AM CST Mon Jan 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...
A persistent large-scale upper-level trough is forecast to remain
over the east-central U.S. during the Day 4 to 8 period. This
pattern will be favorable for repeated cold air intrusions into the
continental U.S late this week into early next week. As a result,
cool and dry conditions are expected to remain in place over much of
the nation, making thunderstorm development unlikely in most areas.
No severe threat is forecast to develop over the continental U.S.
through early next week.

..Broyles.. 01/12/2026

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ACUS48 KWNS 130937
SWOD48
SPC AC 130935

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0335 AM CST Tue Jan 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...
A persistent eastern U.S large-scale upper-level trough is forecast
to remain in place through the Day 4 to 8 period. As a result,
northwesterly mid-level flow is forecast over much of the
continental U.S. In response, multiple cold air intrusions are
expected to take place across the central and eastern U.S. This will
keep a relatively dry and cold airmass over much of the nation
through early next week. For this reason, conditions will be
unfavorable for thunderstorms in most areas, and a severe threat is
not forecast in the Day 4 to 8 period.

..Broyles.. 01/13/2026

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ACUS48 KWNS 140931
SWOD48
SPC AC 140930

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0330 AM CST Wed Jan 14 2026

Valid 171200Z - 221200Z

...DISCUSSION...
Medium-range guidance generally indicates that amplified mid-level
troughing, evolving by late week to the east of the Rockies, will be
maintained through this coming weekend, before a fairly prominent
ridge near and offshore of the Pacific Northwest/British Columbia
coast weakens and redevelops to the west/northwest. However, even
as flow trends less amplified, it appears that a broadly confluent
westerly to northwesterly regime to the east of the Rockies may
continue to support a series of southeastward developing cold
surface ridges. Toward the middle of next week, this may become
less of an influence across the southwestern into western Gulf
Basin, beneath a belt of strengthening mid/upper westerlies
emanating from the subtropical eastern Pacific. It is possible that
low-level moistening and forcing for ascent could become supportive
of sufficient destabilization for thunderstorm development by
Tuesday/Wednesday across the northwestern Gulf. However, it is not
yet clear that this will impact areas inland of the Gulf coast, or
become particularly strong.

..Kerr.. 01/14/2026

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ACUS48 KWNS 150949
SWOD48
SPC AC 150947

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CST Thu Jan 15 2026

Valid 181200Z - 231200Z

...DISCUSSION...
Medium-range models continue to indicate that highly amplified
mid-level troughing will persist across much of North America (to
the east of the Rockies) and the Gulf Basin through this coming
weekend into early next week, when an initially prominent ridge near
the British Columbia/Pacific Northwest coast begins to weaken and
perhaps redevelop to the west/northwest. Thereafter, sizable spread
remains evident within and among the various model output concerning
shorter wavelength developments and blocking within the larger-scale
split flow across the mid-latitude eastern Pacific, and the impacts
on the downstream flow remain unclear.

In general, it still appears that the Gulf Coast states and Gulf
Basin may come under the increasing influence of a strengthening
belt of westerlies emanating from the subtropical eastern Pacific,
and troughing may tend to dig within the mid-latitude westerlies
near and inland of the Pacific coast through mid to late next week.
However, even with guidance indicating potential for modest surface cyclogenesis to the lee of the southern Rockies by the end of the
period, it does not appear that moist return flow off a modifying
Gulf boundary-layer will yet become supportive of appreciable inland destabilization.

..Kerr.. 01/15/2026

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ACUS48 KWNS 160826
SWOD48
SPC AC 160825

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 AM CST Fri Jan 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
Broad upper troughing will persist across much of the CONUS from the
Rockies to the Eastern Seaboard during the Day 4-8 period. Surface
high pressure will largely keep Gulf moisture well offshore, with
cold air intrusions into the Plains and eastern U.S. precluding much
in the way of thunderstorm potential.

The exception may be briefly on Day 6/Wednesday across portions of
the Texas Coastal Plain vicinity. As a reinforcing shortwave upper
trough ejects across the Rockies, lee surface low development over
western TX will allow for very modest Gulf moisture to filter into south/southeast TX. A cold front will sweep south/southeast during
the evening/overnight and isolated thunderstorms could develop.
Severe potential appears low given modest moisture/limited
destabilization.

..Leitman.. 01/16/2026

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ACUS48 KWNS 160836
SWOD48
SPC AC 160834

Day 4-8 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0234 AM CST Fri Jan 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
Broad upper troughing will persist across much of the CONUS from the
Rockies to the Eastern Seaboard during the Day 4-8 period. Surface
high pressure will largely keep Gulf moisture well offshore, with
cold air intrusions into the Plains and eastern U.S. precluding much
in the way of thunderstorm potential.

The exception may be briefly on Day 6/Wednesday across portions of
the Texas Coastal Plain vicinity. As a reinforcing shortwave upper
trough ejects across the Rockies, lee surface low development over
western TX will allow for very modest Gulf moisture to filter into south/southeast TX. A cold front will sweep south/southeast during
the evening/overnight and isolated thunderstorms could develop.
Severe potential appears low given modest moisture/limited
destabilization.

..Leitman.. 01/16/2026

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ACUS48 KWNS 170856
SWOD48
SPC AC 170855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 AM CST Sat Jan 17 2026

Valid 201200Z - 251200Z

...DISCUSSION...
Convective potential will remain low for most of the CONUS during
the Day 4-8 period as persistent troughing envelops much of the
country. However, a couple chances for thunderstorm activity may
develop from TX to the Lower MS Valley vicinity on Day 5/Wed and
possibly toward the end of the period heading into the weekend.
These chances will occur as modified Gulf moisture impinges on the
TX coastal vicinity on Wednesday as an upper trough moves across the
Plains toward the MS Valley. Moisture return, in response to a
developing low in the lee of the southern Rockies, will remain
shallow, but could be sufficient for isolated thunderstorms across
portions of southeast TX into LA Wednesday afternoon into early
Thursday morning.

Some guidance suggests a weak upper shortwave trough and enhanced
southwesterly flow could overspread the Gulf Basin during the
weekend, bringing some deeper boundary layer moisture into portions
of the western and central Gulf coast states. However, guidance
varies considerably and run-to-run consistency is poor.

..Leitman.. 01/17/2026

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ACUS48 KWNS 180847
SWOD48
SPC AC 180845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0245 AM CST Sun Jan 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
A large-scale upper trough will develop eastward across the Plains
and eastern U.S. on Days 4-5/Wed-Thu. As this occurs, some modest
Gulf moisture will spread across east TX toward the Lower MS Valley
ahead of a cold front. Some low potential for thunderstorms will be
possible, but the modest moisture return will limit instability and
severe potential is low.

Beyond Day 5/Thu, forecast guidance is not in very good agreement
with large spread resulting in greater than normal uncertainty. The
control member of the ECMWF appears to be an outlier, showing some
increasing severe potential across the Gulf Coast states toward the
end of the forecast period. However, the GFS and EC-AIFS keep any
Gulf moisture offshore, precluding severe potential. Given these
large model discrepancies, severe probabilities seem low for now.

..Leitman.. 01/18/2026

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ACUS48 KWNS 190932
SWOD48
SPC AC 190931

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CST Mon Jan 19 2026

Valid 221200Z - 271200Z

...DISCUSSION...
Severe potential is expected to be low during the Day 4-8 period.
Some modest Gulf moisture will impinge on the coastal regions from
TX into MS/AL/FL beginning Day 4/Thu. Warm advection will allow for
showers and perhaps isolated thunderstorms, but weak forcing for
ascent and only very minor instability will preclude severe
potential. By Day 5-6/Fri-Sat, a deepening upper trough over the
western U.S. will develop east across portions of the Plains and
Midwest. A strong arctic cold front will move across the middle of
the country, ushering in another punch of cold to very cold air and
once again shunting Gulf moisture offshore. Some thunderstorm
activity could occur ahead of this front across the Gulf coast
states, but deeper moisture return is not expected and will be
insufficient for severe storms. Surface high pressure and a
cold/stable airmass will persist over much of the CONUS behind the
arctic cold front on Days 7-8/Sun-Mon.

..Leitman.. 01/19/2026

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ACUS48 KWNS 200853
SWOD48
SPC AC 200852

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0252 AM CST Tue Jan 20 2026

Valid 231200Z - 281200Z

...DISCUSSION...
An arctic airmass will settle across much of the CONUS east of the
Rockies on Days 4-5/Fri-Sat. Resulting strong high pressure and
cold/dry/stable conditions will persist over much of the country
throughout the period. However, some thunderstorm potential could
develop across portions of the Gulf Coast states/Southeast on Days
4-6/Fri-Sun as a surface cold front progresses east/southeast.
Modified Gulf moisture will be in place near the immediate Gulf
Coast. Warm advection in the low-levels could result in isolated
thunderstorms near or just to the cool side of the cold front Friday
afternoon across parts of TX, spreading east/northeast across the
Southeast through Saturday and early Sunday. Instability should
remain weak as better moisture remains offshore, and due to
convection becoming undercut by the cold front.

..Leitman.. 01/20/2026

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