ACUS48 KWNS 200848
SWOD48
SPC AC 200846

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Sat Sep 20 2025

Valid 231200Z - 281200Z

...DISCUSSION...
A complex, low-predictability upper pattern will exist next week and
should eventually evolve into a closed upper low somewhere across
the eastern CONUS by the end of the week. The operational ECMWF and
GFS have significantly different evolution of the upper pattern,
almost switching places from the solution each showed 24 hours ago.
The ECMWF is now more progressive with a large cutoff low from the
GFS by Wed/D5 and Thu/D6. Even the EPS and GEFS (which showed
similar 500mb solutions 24 hours ago) have diverged and have lead to
increasing predictability concerns. Therefore, beyond Day 4, some
severe weather chances are possible within the warm sector ahead of
a surface front. However, significant differences in timing and
evolution of the pattern cast uncertainty on the overall threat.

...Day 4/Tuesday...
As the stronger mid-level trough emerges across the Plains Monday
night, a low-level jet will strengthen across Oklahoma. Therefore, a
MCS will likely be ongoing at 12Z Tuesday in the Oklahoma vicinity.
Moderate destabilization is forecast to the south of the remnant
MCS/outflow boundary on Tuesday. This region will likely be the
focus for some severe weather threat. It is unclear how the
Monday/D3 convection will evolve and how that may impact Tuesday,
but there is some potential for severe storms Tuesday
afternoon/evening. Once the evolution of the mid-level trough and
location of Monday night convection becomes more clear, severe
weather probabilities may be needed.

..Bentley.. 09/20/2025

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ACUS48 KWNS 210741
SWOD48
SPC AC 210740

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0240 AM CDT Sun Sep 21 2025

Valid 241200Z - 291200Z

...DISCUSSION...
A mid-level trough will amplify across the eastern CONUS on
Wednesday and Thursday with differing model solutions of the trough
evolution by next weekend and beyond. Regardless of the exact
solution, severe weather chances should be low from Saturday and
beyond as high pressure builds into the eastern CONUS and pushes
moisture offshore into the Atlantic and Gulf. Some severe weather is
possible across portions of the Southeast on Day 4/Wed to Day 6/Fri
as moisture remains onshore ahead of the mid-level trough.

...D4/Wed - Lower Mississippi River Valley...
Upper 60s to low 70s dewpoints are anticipated within the Lower
Mississippi River Valley on Wednesday. A zone of moderate
instability may develop within this moisture plume from Louisiana
into Arkansas and Mississippi. Guidance varies greatly on the
evolution of the mid-level trough as it advances east on Wednesday.
This will have a significant impact on the specific location and
intensity of any severe weather threat on Wednesday. However, even
if a less amplified, more subdued mid-level pattern evolves, some
severe weather could exist across the Lower Mississippi Valley as
moderate mid-level flow overspreads moderate instability within the
region.

..Bentley.. 09/21/2025

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ACUS48 KWNS 220835
SWOD48
SPC AC 220833

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0333 AM CDT Mon Sep 22 2025

Valid 251200Z - 301200Z

...DISCUSSION...
A positively tilted mid-level trough around the Great Lakes on
Thu/D4 will move across the Northeast by Fri/D5. A weak surface low
will move through the eastern Great Lakes on Thursday with a cold
front extending southwest from that low. Upper 60s to low 70s
dewpoints ahead of the cold front will support some instability, but
it will remain mostly weak amid weak lapse rates. Moderate mid-level southwesterly flow will provide ample shear for storm organization
if pockets of greater instability can develop. At this time, it
appears a few isolated strong to severe storms may be possible from
the Carolinas to the Mid-Atlantic, but a more organized severe
threat is not anticipated.

On D5/Friday the remnant cold front will likely reside somewhere
near the Southeast coast. A few stronger storms will be possible
along this front on Friday before it pushes into the Atlantic on
Friday night.

In the wake of this cold front, high pressure will build into much
of the eastern CONUS. This will result in low severe weather
probabilities amid a dry, continental airmass. Rich low-level
moisture will remain offshore into the early part of next week and
keep severe weather potential low.

..Bentley.. 09/22/2025

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ACUS48 KWNS 230845
SWOD48
SPC AC 230843

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CDT Tue Sep 23 2025

Valid 261200Z - 011200Z

...DISCUSSION...
A frontal zone will linger along the Southeast coast on Friday. A
few strong storms are possible along this front given the moist
airmass in the region. High pressure and a continental airmass will
build into the eastern CONUS in the wake of this front. This should
result in minimal severe weather potential across much of the CONUS
this weekend and into next week. Operational and ensemble guidance
shows a closed low developing across the Southeast this weekend and
lingering through the middle of next week. Richer moisture may
advect inland to the east and north of this low, and spread
thunderstorms inland, but severe weather chances should still remain
low given weak lapse rates and instability and relatively weak
shear.

..Bentley.. 09/23/2025

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ACUS48 KWNS 240825
SWOD48
SPC AC 240824

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0324 AM CDT Wed Sep 24 2025

Valid 271200Z - 021200Z

...DISCUSSION...
Surface high pressure will dominate much of the eastern CONUS this
weekend and into early next week with dry conditions anticipated.
The only exception may be across the Southeast where tropical
moisture may move inland early next week with some rain and
thunderstorm chances.

Western CONUS mid-level troughing for much of the period will
support lee surface troughing across the northern and central High
Plains. Northerly flow across the Gulf of America should limit rich
moisture inland early next week. Therefore, some residual moisture
may result in weak instability across the central and northern High
Plains, but thunderstorm potential will likely be limited with even
lower severe weather potential.

..Bentley.. 09/24/2025

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ACUS48 KWNS 250909
SWOD48
SPC AC 250908

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0408 AM CDT Thu Sep 25 2025

Valid 281200Z - 031200Z

...DISCUSSION...
Ridging will dominate much of the eastern 2/3rds of the CONUS during
the extended forecast period which will limit thunderstorm activity.
The exception will be across the Southeast United States into the
Mid-Atlantic where a weak cut-off low is forecast to persist into
next week. Some tropical moisture may advect northwestward and bring
some thunderstorm activity to portions of the Southeast into the
Carolinas and Mid-Atlantic. However, instability and shear should
both remain weak and limit any severe weather potential.

A large-scale western CONUS trough will shift east across the
northern Rockies by the middle of next week. This may result in some thunderstorm activity along the lee trough. However, moisture (and
thus severe weather potential) should remain limited given continued
northerly flow across the Gulf of America and southern United
States.

..Bentley.. 09/25/2025

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ACUS48 KWNS 260833
SWOD48
SPC AC 260832

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0332 AM CDT Fri Sep 26 2025

Valid 291200Z - 041200Z

...DISCUSSION...
It appears that an amplification within the westerlies will quickly
translate inland of the North American Pacific coast, across Canada/
adjacent portions of the northern U.S into the northern Atlantic
through the early to middle portion of next week. In its wake,
medium-range guidance suggests a return to a more zonal regime, with
stronger flow confined to the northern mid-latitudes while troughing
is maintained within weaker flow across the Gulf Basin through
Southeast vicinity.

The risk for organized severe convection appears low through the
period, with perhaps the most notable conditional severe weather
potential accompanying a pair of tropical cyclones forming across
parts of the subtropical western Atlantic. While it currently
appears probable that Humberto will turn northeastward/eastward well
offshore of the Atlantic Seaboard, guidance continues to indicate at
least some possibility that a developing cyclone to its west could
approach or migrate inland of Atlantic coastal areas anywhere from
Florida to the Carolinas. However, even if this occurs, it is not
certain that this will be accompanied by the inland advection of a
sufficiently moist/buoyant boundary-layer air mass to support an
appreciable risk for tornadoes.

..Kerr.. 09/26/2025

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ACUS48 KWNS 270845
SWOD48
SPC AC 270843

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CDT Sat Sep 27 2025

Valid 301200Z - 051200Z

...DISCUSSION...
Potential Tropical Cyclone Nine may approach coastal South Carolina
early in the period, before probably stalling near or offshore, then accelerating away from the coast into the western Atlantic. This is
likely to be influenced by some combination of a lingering frontal
zone near the Carolina coast, an initial increasing proximity of
Humberto to its east, and cool surface ridging building across the
Northeast through the lee of the Appalachians, in the wake of an
amplifying mid-level trough off the north Atlantic coast during the
early to middle portion of next week. However, even if it does
migrate inland at some point, as some model output indicates is at
least possible, probabilities for the inland advection of a
sufficiently moist and buoyant boundary layer to support an
appreciable risk for tornadoes still appears low.

Otherwise, developments within the westerlies off the mid-latitude
Pacific into North America remain unclear through the latter portion
of the coming week into next weekend. Guidance now appears to
indicate a more amplified regime, including one or more short wave perturbations emerging from evolving large-scale troughing across
the West. However, a slow to develop moist return flow off the Gulf
into the interior U.S. may continue to preclude an appreciable risk
for organized severe thunderstorm development.

..Kerr.. 09/27/2025

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ACUS48 KWNS 280826
SWOD48
SPC AC 280825

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0325 AM CDT Sun Sep 28 2025

Valid 011200Z - 061200Z

...DISCUSSION...
Strong cyclogenesis within the westerlies near the Aleutians late
this week into next weekend may lead to the development of an
increasingly prominent blocking pattern over the eastern
mid-latitude Pacific into western North America. This may include
an evolving low near the California coast, to the southeast of
building mid/upper high over the northeastern Pacific by the end of
the period. In general, though, stronger westerlies are forecast to
remain confined to the northern mid-latitudes, with little potential
for substantive cyclogenesis to the lee of the Rockies, and moist
return flow off the Gulf Basin. This likely will maintain generally
low convective potential across the nation.

..Kerr.. 09/28/2025

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ACUS48 KWNS 290830
SWOD48
SPC AC 290828

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0328 AM CDT Mon Sep 29 2025

Valid 021200Z - 071200Z

...DISCUSSION...
Latest model output is not much different from prior runs concerning
the continuation of generally low convective potential across the
U.S. into and through the medium-range period. Guidance continues
to suggest that an increasingly amplified regime across the
mid-latitude eastern Pacific into western North America could lead
to the evolution of a prominent blocking pattern late this week into
next weekend. By early next week, this may include a building
mid-level high over the northeastern Pacific, near the British
Columbia/Pacific Northwest coast, flanked by a pair of evolving lows
at somewhat lower latitudes, including one over the U.S.
Intermountain West. Otherwise, the stronger westerlies may retreat
to somewhat higher latitudes, and mid/upper ridging may build in the
southern mid- to subtropical latitudes east of the Rockies and
Mexican Plateau. Significant surface cyclogenesis still appears
unlikely to the east of the U.S. Rockies, and low-level moisture
return off the Gulf Basin may be slow to develop.

..Kerr.. 09/29/2025

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ACUS48 KWNS 300823
SWOD48
SPC AC 300822

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0322 AM CDT Tue Sep 30 2025

Valid 031200Z - 081200Z

...DISCUSSION...
Late this work week through the weekend, medium-range models
continue to indicate mid/upper flow amplification across the
mid-latitude eastern Pacific into North America, which may lead to
the evolution of an increasingly prominent blocking high offshore of
the British Columbia/Pacific Northwest coast. This would probably
be flanked by persistent troughing at somewhat lower latitudes,
including California coastal areas into the Great Basin. However,
the spread within/among the model output is sizable concerning this
and subsequent developments through early next week.

Stronger and more progressive westerlies, and potential for
significant surface cyclogenesis, may remain confined to the higher
latitudes. However, there does appear a consensus within the
medium-range output of modestly deepening surface troughing across
parts of the central Great Plains into Upper Midwest (roughly along
an axis from the Front Range through Minnesota) by this weekend,
perhaps as one notable short wave perturbation accelerates
northeastward out of the Intermountain West. In the presence of
steep lower/mid-tropospheric lapse rates and strengthening flow,
this could provide a focus for strong thunderstorm development
Saturday and/or Sunday. However, due to the continuing lack of a
substantive moist return flow off the Gulf, the potential for
organized severe storms still appears low.

..Kerr.. 09/30/2025

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ACUS48 KWNS 010851
SWOD48
SPC AC 010850

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0350 AM CDT Wed Oct 01 2025

Valid 041200Z - 091200Z

...DISCUSSION...
Downstream of a building mid-level ridge, and perhaps evolving
embedded high over the northeastern Pacific, it appears that
large-scale troughing will be maintained across the Great
Basin/Southwest vicinity through this coming weekend and beyond.
However, an initially notable short wave trough, digging into the
Great Basin by late this week, is forecast to accelerate across and
northeast of the Rockies, through northern Ontario, Saturday into
early next Monday morning. The extent to which it maintains
strength as it eventually consolidates into mid-level troughing
shifting across and east of the Canadian Prairies, remains unclear.
But, latest medium-range output appears to be trending deeper with
developing surface troughing, and perhaps a relatively compact
evolving surface cyclone, northeast of the Front Range through the
northern Great Plains/Upper Midwest vicinity.

Preceded by a northeastward advecting plume of elevated mixed-layer
air, strengthening flow and shear could contribute to potential for
organized severe convection across parts of western/central Nebraska
through the eastern Dakotas/western Minnesota late Saturday into
Saturday evening, and perhaps farther east across the Upper
Midwest/adjacent Great Lakes vicinity on Sunday. However, this
threat still appears largely conditional. It will probably take
greater boundary-layer moistening than is currently suggested
possible by the medium-range output to support more than relatively
minor severe weather potential in the form of a few strong gusts, in
the presence of thermodynamic profiles characterized by a deeply
mixed boundary layer with sizable lower/mid-tropospheric dew point
spreads.

Into the early through middle portion of next week, the mid/upper
flow evolution becomes more unclear, but guidance continues to
indicate little potential for organized severe thunderstorms.

..Kerr.. 10/01/2025

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ACUS48 KWNS 020848
SWOD48
SPC AC 020847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Thu Oct 02 2025

Valid 051200Z - 101200Z

...DISCUSSION...
Medium-range guidance indicates that blocking within the westerlies
across the mid-latitude eastern Pacific will remain prominent into
the middle to latter portion of next week. However, one mid-level
high forming off the Pacific coast this weekend may be relatively
short-lived, and subsequent developments off the Pacific into North
America remain unclear, based on rather large spread apparent in the
model output.

Early in the period, a still notable, but perhaps weakening,
mid-level short wave perturbation, and associated compact surface
cyclone, may quickly migrate from the eastern Dakotas through
northwestern Ontario during the day Sunday. In the presence of
seasonably strong and sheared lower/mid-tropospheric wind fields,
there appears at least some potential for renewed strong to severe
thunderstorm development, mainly across parts of north central
Minnesota through the western Lake Superior vicinity by Sunday
evening. However, mostly due to a continuing lack of better
low-level moisture return, potential for destabilization supportive
of more than a relatively isolated/marginal severe risk still seems
low or at least uncertain.

Elsewhere, there appears at least some signal for increasing
convective potential ahead of an amplifying short wave trough and
associated cold front advancing southeast of the lower Great Lakes
region, which could impact the Northeastern urban corridor by late
Wednesday. At this point, this appears most notable in ECMWF/ECENS
related output, compared to other model output, at a period of
increasing model spread and low predictability.

..Kerr.. 10/02/2025

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ACUS48 KWNS 030817
SWOD48
SPC AC 030816

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0316 AM CDT Fri Oct 03 2025

Valid 061200Z - 111200Z

...DISCUSSION...
A cold front is forecast to move east across much of the Midwest and Northeast/Mid-Atlantic vicinity through Day 6/Wed. This could result
in increasing thunderstorm potential ahead of this feature given a
moist prefrontal boundary layer. Most guidance suggests instability
will be limited however, likely due to a combination of weak lapse
rates and areas of cloudiness/showers ahead of the front. Severe
thunderstorm potential appears low.

Further west, the ECMWF suite of guidance suggests an upper
shortwave trough may eject across the central Rockies into the
central Plains around Day 6 or 7/Wed or Thu, with some southerly
return flow bringing Gulf moisture northward ahead of this feature.
However, the GFS suite of guidance is delayed with this feature
until near/after Day 8/Fri. Thunderstorm could increase across parts
of the Plains late in the forecast period, but uncertainty/model
spread is quite large.

..Leitman.. 10/03/2025

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ACUS48 KWNS 040840
SWOD48
SPC AC 040839

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0339 AM CDT Sat Oct 04 2025

Valid 071200Z - 121200Z

...DISCUSSION...
A cold front will move offshore the Northeast coast and develop
southward in the Mid-South/TN Valley area early the forecast period
(around days 4-5/Tue-Wed). Severe thunderstorm potential is expected
to be low as the front progresses given limited destabilization
across the warm sector.

The second half of the forecast period (days 6-8/Thu-Sat) becomes
more uncertain as spread among forecast guidance increases
considerably. Most guidance shows upper ridging building over the
Plains through much of the period. Toward the weekend, an upper
trough may develop southeast across the eastern half of the CONUS,
but details regarding timing and spatial evolution of this feature
vary considerably, resulting in low forecast confidence.

..Leitman.. 10/04/2025

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ACUS48 KWNS 050818
SWOD48
SPC AC 050816

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0316 AM CDT Sun Oct 05 2025

Valid 081200Z - 131200Z

...DISCUSSION...
Surface high pressure is forecast to build across portions of the
Midwest and Eastern U.S. behind a cold frontal passage on Day
4-5/Wed-Thu. This high pressure will remain in place for much of the
period, and with the cold front developing south toward the Gulf
coast states, continental low-level trajectories east of the MS will
result in a mostly stable airmass.

Some southerly return flow is possible across the southern/central
Plains late in the period beneath an upper ridge as surface lee
troughing develops ahead of an upper trough developing southeast
across parts of the Plains into the eastern half of the CONUS.
However, severe potential appears low as any strong large-scale
ascent and increasing deep layer shear will remain displaced from
better boundary layer moisture.

..Leitman.. 10/05/2025

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ACUS48 KWNS 060808
SWOD48
SPC AC 060806

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0306 AM CDT Mon Oct 06 2025

Valid 091200Z - 141200Z

...DISCUSSION...
Upper ridging will persist over the Plains through at least Day
5/Fri, while upper troughing develops over the East. Surface high
pressure and a cold front offshore the Atlantic and Gulf coasts will
preclude severe thunderstorm potential due to a mainly dry and
stable airmass east of the Rockies.

By Day 6/Sat and beyond, most medium-range guidance depicts a more
progressive upper pattern, with one or more upper troughs developing
across the West and into the Plains. As this occurs, surface lee
troughing and cyclogenesis over the northern Plains late in the
period should allow for some meager Gulf return flow/increasing
moisture. However, severe potential still appears low given any more appreciable moisture return likely will still be offset from
stronger deep-layer flow and large-scale ascent focused over the central/northern Plains.

..Leitman.. 10/06/2025

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ACUS48 KWNS 030949
SWOD48
SPC AC 030948

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CST Mon Nov 03 2025

Valid 061200Z - 111200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
A mid-level trough is forecast to move quickly eastward into the
Great Plains on Thursday, and into the Ohio and Tennessee Valleys on
Friday. Ahead of the system, low-level moisture return is forecast
to be limited. In spite of this, weak instability is expected to
develop ahead of the trough as it progresses eastward across the
central U.S. Thunderstorms will be possible ahead of the trough from
the central Plains to the mid Mississippi Valley Thursday afternoon
and evening, and into the Ohio and Tennessee Valleys on Friday. Any
severe threat on these two days should remain isolated due to the
lack of instability.

On Saturday, a large-scale mid-level trough is forecast to dig
southeastward into the Mississippi Valley. Ahead of the trough,
low-level moisture return is expected to take place across much of
the Southeast. Thunderstorm development is currently forecast along
the northern edge of a moist airmass, in the Tennessee Valley
Saturday afternoon and evening. A potential will exist for scattered
severe storms. However, there is considerable uncertainty concerning
the magnitude of any severe threat, and where the greatest threat
will be. Some solutions suggest that most of the storms will be
located to the north of the strongest instability, which would be
problematic for a greater severe threat. At this time, will continue "predictability too low" for Saturday.

...Sunday/Day 7 and Monday/Day 8...
On Sunday, the large-scale mid-level trough is forecast to move
eastward into the Ohio and Tennessee Valleys, as a cold front
advances into the Atlantic Coastal States. Thunderstorms will be
possible ahead of the front during the afternoon from Georgia
northward into the Carolinas and Mid-Atlantic. An isolated severe
threat will be possible, although uncertainty is substantial at this
range. The front is forecast to move off the Atlantic Coast on
Monday, reducing the potential for thunderstorms across the
continental U.S.

..Broyles.. 11/03/2025

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ACUS48 KWNS 100848
SWOD48
SPC AC 100846

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 AM CST Mon Nov 10 2025

Valid 131200Z - 181200Z

...DISCUSSION...
Modified return flow will persist across the western Gulf late week,
with a maritime tropical airmass reaching the TX Gulf Coast next
weekend. This will support a return of severe-storm potential to
mainly the western and central Gulf Coast States.

Downstream evolution of a broad upper trough along the West Coast on D4/Thursday is the primary forecast challenge into the weekend.
While the 00Z runs of the EC, GFS, and CMC have converged to greater
alignment with the handling of the southern-stream shortwave trough
across the Southwest and northern Mexico, run-to-run continuity
remains poor. In addition, differing scenarios in other guidance
such as a much slower cutoff low in the EC-AI, along with a large
amount of spread across the GEFS/ECENS, all suggest a fairly
unpredictable pattern continues. This is further supported by WPC's
latest EPD mention of well below-average confidence in this
weekend's forecast.

..Grams.. 11/10/2025

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ACUS48 KWNS 130900
SWOD48
SPC AC 130858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Mon Oct 13 2025

Valid 161200Z - 211200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
On Thursday, a mid-level ridge is forecast to move eastward into the Mississippi Valley, as a low and an associated shortwave trough move northeastward into the northern Rockies and northern Plains.
Thunderstorm development is expected Thursday afternoon along and
ahead of a cold front from central Nebraska into the eastern
Dakotas. An isolated severe threat will be possible, but should be
marginal due to weak instability.

From Friday into Saturday, a large-scale mid-level trough is
forecast to move eastward from the central Rockies and Intermountain
West into the Great Plains. Scattered thunderstorms will be possible
Friday afternoon and evening ahead of the trough along and near an
axis of instability from Oklahoma northeastward into northwest
Missouri. Forecast instability and deep-layer shear appear
sufficient for an isolated severe threat.

Friday night, low-level moisture advection is forecast to markedly
increase as surface dewpoints in the lower to mid 60s F overspread
the Ark-La-Tex, Ozarks and mid Mississippi Valley. Moderate
instability is expected to develop early in the day on Saturday
across parts of the moist sector, where moderate to strong
deep-layer shear will be in place. Thunderstorms that form along and
near the axis of strongest instability should obtain a severe
threat. Supercells with severe wind gusts, hail and tornado
potential will be possible. The magnitude of the severe threat will
be greatest in areas that remain unaffected by morning thunderstorm
activity. The severe threat should spread eastward into the lower to
mid Mississippi Valley Saturday evening and into the overnight
period. Although lingering uncertainties exist, confidence in the
model solutions is great enough to add a 15 percent area over parts
of Ark-La-Tex, Ozarks and lower to mid Mississippi Valley.

...Sunday/Day 7 and Monday/Day 8...
The mid-level trough is forecast to move eastward across the lower
to mid Mississippi Valley on Sunday and to the mid Atlantic Seaboard
on Monday. Thunderstorms will be ongoing Sunday morning, ahead of a
cold front moving through the Ohio and Tennessee Valleys. New
convective development is expected during the day on Sunday ahead of
the front as surface temperatures warm. Thunderstorm development
should also occur on Monday ahead of the front. However, instability
is forecast to remain relatively weak across much of the moist
sector on Sunday and Monday, suggesting the severe threat in most
areas will remain relatively isolated.

..Broyles.. 10/13/2025

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ACUS48 KWNS 190854
SWOD48
SPC AC 190853

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0353 AM CDT Sun Oct 19 2025

Valid 221200Z - 271200Z

...DISCUSSION...
In the wake of the strong upper low over the eastern US,
thunderstorm chances will be temporarily muted across the central
and eastern US with surface high pressure and offshore flow limiting
available instability. Isolated thunderstorms are possible late
D4/Wed over parts of the Southwest ahead of a southern stream
shortwave trough moving onshore from the eastern Pacific. However,
moisture and buoyancy should be quite sparse, suggesting only
isolated coverage and negligible severe risk.

...Southern Plains to the lower MS Valley D5-D8...
The shortwave trough over the Southwest is forecast to move into the
southern Plains as high pressure over the eastern US settles along
the Gulf Coast. As the trough crosses the Rockies, a lee low should
develop, allowing for modest low-level moisture return over parts of
the lower MS Valley and southern Plains. Cooling mid-level
temperatures and moistening of the airmass over TX/OK should support
increasing thunderstorm chances through the end of the week, with
thunderstorm potential extending into the ArkLaTex and lower MS
Valley next weekend.

Some severe potential is apparent as westerly flow aloft increases
amidst the returning moisture/instability. However, details such as
the degree of destabilization, timing/structure of the upper trough,
and the potential for organized storms remains highly uncertain. 15%
severe probabilities could be introduced in future outlook cycles
should confidence in organized severe potential increase.

..Lyons.. 10/19/2025

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ACUS48 KWNS 200859
SWOD48
SPC AC 200858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Mon Oct 20 2025

Valid 231200Z - 281200Z

...DISCUSSION...
Severe storm potential is likely to increase through the extended
forecast period as a series of upper troughs and enhanced
southwesterly flow aloft return to the central and southeastern
CONUS. The primary uncertainty remains the degree of moisture return
and instability.

...D4/Thursday-D6/Saturday Southern Plains/ArkLaTex...
A shortwave trough will cross the southern Rockies into the High
Plains supporting lee cyclogenesis Thursday and Thursday night. In
the wake of the earlier frontal passage, modest low-level moisture
return is expected to take place east of the low and a lee trough
over the southern Plains as a warm front lifts northward. Cooling
mid-level temperatures will allow for diurnal destabilization and
some organized severe potential as westerly flow aloft also
increases. Strong to potentially severe storms are possible
D4/Thursday and D5/Friday in vicinity of the surface low and warm
front across KS/OK, and along the lee trough into the TX Panhandle.
However, confidence in the overall severe risk and its evolution is
low, pending sufficient moisture return and the timing of the upper
trough.

Some severe potential will likely shift eastward into the ArklaTex
D6/Saturday as the upper low moves eastward and low-level moisture
return continues. Confidence in the severe risk is limited, owing to
the potential for several prior days of convection.

...Eastern Plains and Mid MS Valley D7-D8...
Greater severe potential may develop towards the end of the extended
forecast period as a deep upper trough matures over the Plains
D7/Sunday and moves into the Midwest/MS Valley D8/Monday. Ensemble
and deterministic guidance show a strong cold front and low with
sufficient moisture/instability for severe storms capable of all
hazards from the eastern Plains and MS Valley late this weekend into
early next week. 15% severe probabilities could be needed in future
outlook cycles should model solutions converge on timing and
location of the greatest severe risk.

..Lyons.. 10/20/2025

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ACUS48 KWNS 040909
SWOD48
SPC AC 040908

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0308 AM CST Tue Nov 04 2025

Valid 071200Z - 121200Z

...DISCUSSION...
...D4/Friday...
An area-of-interest, sufficient for a Predictability Too Low
highlight, appears centered on the OH Valley to Deep South. A
large-scale mid/upper trough should consist of several embedded
shortwave impulses progressing east from Hudson Bay through the
central to eastern CONUS. Primary surface cyclone is expected to
shift from the Upper Great Lakes into QC, with a trailing cold front
to its southwest undergoing frontolysis in the TN Valley/Deep South
by Friday night. Modified moisture return from the southern Gulf may
support moderate buoyancy over the Lower MS Valley, with a plume of
weak buoyancy extending into the OH/TN Valleys ahead of the front. A
belt of strong mid-level westerlies will yield favorable deep-layer
shear for organized severe potential. Latest GEFS-based SPC/NSSL ML
probs have trended upward with severe indications, more aggressive
than yesterday's available NCAR ECENS-based guidance. Overall setup
may tend to favor a more mesoscale-driven 15% area given uncertainty
on timing of convective development along the southwest extent of
the weakening front and the degree of destabilization where ascent
is stronger to the northeast.

...D6/Sunday...
Substantial amplification of the next mid/upper trough is largely
progged across the central to eastern states late Saturday through
Sunday. This should induce more southerly cyclogenesis across the
North-Central States into the Lower Great Lakes. With the D4 wave
aiding in low-level moisture return from the southern Gulf, latest
guidance indicates seasonably rich dew points may be more prevalent
across the eastern Gulf and South Atlantic Coasts by late weekend.
This signal distinctly lacks run-to-run continuity, but should
foster at least low-probability severe potential across the
Southeast Coastal Plain.

..Grams.. 11/04/2025

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ACUS48 KWNS 180926
SWOD48
SPC AC 180924

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0324 AM CST Tue Nov 18 2025

Valid 211200Z - 261200Z

...DISCUSSION...
...Days 4-5/Fri-Sat - Southeast TX to the Carolinas...

A shortwave upper trough over the southern Plains will migrate east
across the Mid-South on Friday, and exiting the southern
Mid-Atlantic coast by Saturday evening. Gulf moisture will spread
across much of the region ahead of a weak surface low and slowly
moving cold front. Thunderstorms, perhaps some strong, could develop
near the front from southeast TX into the Mid-South and OH/TN Valley
vicinity on Friday into early Saturday. However, instability is
expected to remain weak as boundary layer moisture decreases with
northeast extent. Furthermore, low-level flow will remain veering
and boundary-parallel deep-layer flow will favor more of a
messy/training storm mode. While some low-end severe probabilities
could become necessary in later outlook, potential appears too low
for 15 percent probabilities on Friday.

Thunderstorms will continue to develop eastward into the Carolinas
on Saturday as the cold front continues to sag southeast. Weak
instability will likely preclude severe potential into Saturday.

...Days 6-8/Sun-Tue - Southern Plains...

Spread among forecast guidance increases considerably by Days
6-7/Sun-Mon and confidence/predictability is low. However, in
general another upper trough is expected to deepen across the
Southwestern U.S. early next week, perhaps ejecting into the Plains
sometime around the end of the forecast period. Gulf return flow
will occur across TX ahead of this next trough in a progressive
upper pattern. Increasing moisture and shear as the trough ejects
could support severe potential across the southern Plains early next
week, but details remain uncertain.

..Leitman.. 11/18/2025

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ACUS48 KWNS 140859
SWOD48
SPC AC 140857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Tue Oct 14 2025

Valid 171200Z - 221200Z

...DISCUSSION...
...Friday/Day 4 and Saturday/Day 5...
A large-scale mid-level trough, and an associated cold front are
forecast to move across the central U.S. on Friday and Saturday.
Isolated to scattered thunderstorms are expected to develop from
late Friday afternoon into the evening along and ahead of the front
from the southern Plains northeastward into the lower to mid
Missouri Valley. Ahead of much of the front, MLCAPE is forecast to
peak around 1000 J/kg with 0-6 km shear ranging from 30 to 40 knots.
This should be sufficient for an isolated severe threat. Cells with
potential for large hail and severe wind gusts will be possible.

On Saturday, moisture advection is forecast to markedly increase
ahead of the approaching trough, as surface dewpoints increase into
the 60s F over much of the moist sector. In spite of this,
instability will be tempered over parts of the Ozarks by ongoing
convection Saturday morning. The models suggest that an axis of
moderate instability will develop a bit further west by afternoon,
with MLCAPE increasing to the 1500 to 2000 J/kg range, mainly in the Ark-La-Tex. Thunderstorms that develop along and near the
instability axis should obtain a severe threat. Moderate deep-layer
shear is forecast over much of the moist sector, which will
contribute to a potential for supercells with wind damage, hail and
potentially a tornado threat. Storm mode is still uncertain, and
linear mode could become favored relatively early in the event.
Under this scenario, wind damage would be the most likely of the
three hazards. The severe threat should persist into the overnight
period, as an MCS moves eastward through the lower to mid
Mississippi Valley.

...Sunday/Day 6 to Tuesday/Day 8...
Widespread convection is expected to be ongoing Sunday morning
across the Ohio and Tennessee Valleys southward into the central
Gulf Coast states. This convection, along with abundant cloud cover,
should limit destabilization over much of the moist sector during
the day. In spite of this, an isolated severe threat could develop
in areas where sufficient surface heating takes place, from parts of
northern Florida northward into the southern Appalachians. The
severe threat is expected to diminish across the eastern U.S. on
Monday and Tuesday, as the cold front moves offshore into the
western Atlantic. However, uncertainty is still substantial at this
forecast range.

..Broyles.. 10/14/2025

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ACUS48 KWNS 150858
SWOD48
SPC AC 150857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Wed Oct 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
...Saturday/Day 4...
A large-scale mid-level trough will move through the Great Plains on
Saturday, with a moist airmass in place across the Ark-La-Tex,
Ozarks and lower Mississippi Valley. Within this airmasss, an area
of thunderstorms is likely to be ongoing at the start of the period
across parts of eastern Oklahoma and southwest Missouri. Ahead of
this convection, moisture advection and surface heating will
contribute to a moderately unstable airmass by midday, with
forecasts increasing MLCAPE to around 1500 J/kg across the
Ark-La-Tex. Thunderstorm development appears likely in the early
afternoon over much of Ozarks, where moderate deep-layer shear is
forecast. The ECWMF is forecasting 0-6 km shear in the 40 to 50 knot
range over this part of the moist sector, suggesting a severe threat
will be probable during the afternoon. Wind damage will be possible
with bowing line segments, and low-level shear should be sufficient
for tornadoes. Hail will also be possible, mainly if supercells can
develop. Storm mode still remains uncertain. If the mode goes linear
early in the event, the wind-damage threat could become dominant.
The severe threat should persist through the evening and into the
overnight period, as an MCS moves through the central Gulf Coast
states.

...Sunday/Day 5 and Monday/Day 6...
The mid-level trough is forecast to move through the Ohio and
Tennessee Valleys on Sunday, and to the Atlantic Seaboard on Monday.
Ahead of the trough, scattered thunderstorms with an isolated severe
threat will be possible Sunday and Sunday night, with much of the
convection moving offshore into the Atlantic relatively early on
Monday. An isolated severe threat would still be possible closer to
the mid-level low in parts of the Mid-Atlantic Monday afternoon.

...Tuesday/Day 7 and Wednesday/Day 8...
From Tuesday into Wednesday, a mid-level low is forecast to move
across the southwestern U.S., reaching the southern Rockies by
Wednesday night. If the models are relatively close on the system
timing, an isolated severe threat could develop ahead of the system
Wednesday night across the southern Plains. However, uncertainty at
this range is substantial.

..Broyles.. 10/15/2025

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ACUS48 KWNS 210902
SWOD48
SPC AC 210900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Tue Oct 21 2025

Valid 241200Z - 291200Z

...DISCUSSION...
...D4/Friday-D5/Saturday Southern Plains/ArkLaTex...
The shortwave trough over the southern Plains and associated surface low/Pacific front will gradually move eastward Friday supporting
scattered thunderstorms over parts of TX/OK. Overnight convection
and continued low-level warm air advection is likely to impact the
environment to some degree. This suggests very low predictability
for any organized severe threat. Still, broad ascent, moderate
deep-layer shear, and the potential for destabilization suggests at
least some severe risk may develop from central OK southward toward
the Red River and central TX vicinity Friday.

Low-end severe potential will likely shift eastward into the
ArkLaTex and lower MS Valley D5/Saturday as the upper low moves
farther eastward. Most guidance shows the upper trough beginning to
weaken with the surface features also becoming more ill defined with
time. While the general environment likely will remain supportive of thunderstorms and isolated severe potential, details are sparse.

...Eastern Plains and Mid MS Valley D6/Sunday-D7 Monday...
Higher severe potential may develop towards the end of the extended
forecast period as a Pacific trough and amplified westerly flow
develop over the western US D6/Sunday and move into the Plains and
Midwest D7/Monday. Substantial variability exists between multiple
ensemble and deterministic models regarding the evolution of the
trough and resulting surface pattern. More amplified and less
progressive solutions, along with some ML guidance, show the
potential for a deep surface low and strong cold front to develop
and sweep eastward. Should this occur, robust moisture return for
fall is likely to develop along with strong low and mid-level wind
fields across much of the central US. A favorable synoptic regime
could support widespread severe storm development with sufficient instability/shear overlap for all hazards from the eastern Plains
into the MS Valley and Midwest.

This scenario remains highly uncertain with large variance noted
between both ensemble and deterministic solutions regarding the
structure and timing of the upper trough. Given the degree of
spatial and temporal variance, predictability remains too low to
justify probabilities in the extended forecast. However, 15% or
higher severe probabilities could be needed in future outlook cycles
should guidance trend towards a more unified/higher-end solution.

..Lyons.. 10/21/2025

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ACUS48 KWNS 280822
SWOD48
SPC AC 280820

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0320 AM CDT Tue Oct 28 2025

Valid 311200Z - 051200Z

...DISCUSSION...
In the wake of a substantial cold frontal passage across the East,
generally dry and stable conditions are expected to prevail through
much of the extended range, as a large-scale mid/upper-level trough
and extensive surface ridge persist across the central/eastern CONUS
and limit potential for substantial moisture return.

On D5/Saturday, modest low-level moisture return will be possible
across parts of Deep South TX and the TX Gulf Coast, in response to
a midlevel shortwave trough digging southward across the Great
Plains. Most deterministic and ensemble guidance (aside from the
more aggressive 28/00Z GFS) suggests destabilization will be too
weak to support an organized severe threat, though at least some
thunderstorm activity could accompany this system.

Some thunderstorm potential could linger near the Gulf Coast into
D6/Sunday and D7/Monday, but most guidance suggests only low
potential for substantial inland moisture return and destabilization
into early next week.

..Dean.. 10/28/2025

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ACUS48 KWNS 270848
SWOD48
SPC AC 270847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Mon Oct 27 2025

Valid 301200Z - 041200Z

...DISCUSSION...
An amplified, but stagnant mid-level flow pattern is forecast to
develop over the US late this week continuing into the weekend.
Punctuated, by continued large-scale troughing over the eastern US,
a deep coastal low will develop and move off the Atlantic Coast.
Accompanying the low, a strong cold front is forecast to scour
moisture from much of the continent as surface high pressure builds
behind it. As troughing is maintained to the east, ridging will
build over the western US supporting strong northwesterly flow aloft
over the central CONUS. Strengthening surface high pressure will
favor continued offshore flow and little moisture return. Widespread
cooler and more stable surface conditions are forecast to persist
into early next week with little change in the large-scale pattern.
Thus, thunderstorm chances are low with little severe risk through
the extended forecast period.

..Lyons.. 10/27/2025

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ACUS48 KWNS 290758
SWOD48
SPC AC 290756

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 AM CDT Wed Oct 29 2025

Valid 011200Z - 061200Z

...DISCUSSION...
Organized severe-thunderstorm potential generally appears low
through the extended range, with dry and stable conditions expected
to prevail across most of the CONUS into at least early next week.

On D4/Saturday, a mid/upper-level trough is forecast to amplify over
the central/southern Plains and lower/mid MS Valley. Some modest
low-level moisture return will be possible across parts of south TX
and the TX Gulf Coast during the day, in advance of a reinforcing
cold front. The GFS remains the most aggressive regarding prefrontal destabilization, with other deterministic and ensemble guidance
depicting weaker instability, and a tendency for any storm
development to be primarily anafrontal.

For D5/Sunday and beyond, predictability decreases with time
regarding whether the mid/upper-level trough will remain progressive
as it moves across the Southeast, or if a deep mid/upper-level
cyclone will develop and move only slowly eastward. Most guidance
depicts limited inland moisture return and destabilization, though
the more amplified solutions could support some threat for locally
strong storms across mainly coastal regions of the Southeast into
early next week.

..Dean.. 10/29/2025

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ACUS48 KWNS 050856
SWOD48
SPC AC 050855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 AM CST Wed Nov 05 2025

Valid 081200Z - 131200Z

...DISCUSSION...
Major amplification of the eastern CONUS upper trough appears likely
this weekend, inducing more southerly cyclogenesis across the
North-Central States into the Northeast. A pronounced surface
anticyclone will drive an extensive ridge across the central states,
aiding in progressive cold front movement across the Southeast late
Saturday into Sunday. Ahead of this front, some potential for severe
could yet evolve on D5/Sunday as flow fields strengthen atop a plume
of seasonably rich surface dew points along the eastern Gulf and
South Atlantic Coasts. However, most guidance indicates a fairly dry
frontal passage in this region, amid low RH/weak lapse rates in the
mid-levels.

With a very amplified trough east/ridge west by D6/Monday and a
continental airmass overspreading much of the Gulf, severe potential
should be minimal early next week.

..Grams.. 11/05/2025

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ACUS48 KWNS 060920
SWOD48
SPC AC 060918

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0318 AM CST Thu Nov 06 2025

Valid 091200Z - 141200Z

...DISCUSSION...
Focus for severe potential is on D4/Sunday along the eastern Gulf
and south Atlantic Coastal Plain. Major amplification of the eastern
CONUS upper trough that commences on D3/Saturday will persist
through Sunday. Attendant surface cyclone should track from the
Lower Great Lakes towards coastal southern New England through
Sunday night. Extending southward from this low, a cold front will
push east across the Southeast and largely offshore outside of the
FL Peninsula. While the bulk of deep-layer flow amplification will
be behind the front, strong deep-layer shear should be present
along/ahead of it with at least weak buoyancy. Some guidance has
trended upward with the degree of convective coverage, while others
indicate a fairly dry frontal passage in this region amid low
RH/weak lapse rates in the mid-levels. At this juncture, severe
probabilities appear to be at least 5 but less than 15 percent.

With a very amplified trough east/ridge west by D5/Monday and a
continental airmass overspreading much of the Gulf, severe potential
should be minimal early to middle next week.

..Grams.. 11/06/2025

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ACUS48 KWNS 110921
SWOD48
SPC AC 110919

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0319 AM CST Tue Nov 11 2025

Valid 141200Z - 191200Z

...DISCUSSION...
Bulk of guidance has largely trended towards the more consistent
EC-AIFS with a cutoff closed low near southern CA on D5/Saturday.
The EC-AIFS has been trending slower and more dampened with the
downstream evolution across the southern Rockies into the central
Great Plains into early next week. Most other deterministic guidance
remains faster and farther south with the evolution of this wave and
progress it into the South-Central States.

A maritime tropical airmass should reach the TX Gulf Coast by late
weekend. This should yield a resumption of severe potential into the South-Central States after being negligible in preceding days.
Still, the quartet of latest GEFS-SPC/NSSL and yesterday's ECENS-AI
NCAR probabilistic guidance are each holding at less than 15
percent. If the rest of guidance further follows recent EC-AIFS
trends, severe probabilities may remain marginal and/or
mesoscale-focused on D6-7/Sunday-Monday.

Given signals for another large-scale trough into the Southwest
towards D8/Tuesday and lack of frontal intrusion into the northwest
Gulf with the lead wave, another round of severe potential may
develop around mid-week next week.

..Grams.. 11/11/2025

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ACUS48 KWNS 120859
SWOD48
SPC AC 120857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 AM CST Wed Nov 12 2025

Valid 151200Z - 201200Z

...DISCUSSION...
...Lower Great Lakes/Upper OH Valley on D4/Saturday...
Amplification of a negative-tilt mid-level trough appears probable
from the Canadian Prairies towards the Northeast. Within the
left-exit region of a strengthening mid-level jet, convection should
increase towards late afternoon and especially into the evening
along a sharpening cold front that accelerates southeastward. With
only modified boundary-layer moisture return ahead of the front,
MLCAPE should be quite limited and spatially confined. But a
supercell wind profile combined with pronounced large-scale ascent
should be adequate for at least low severe probabilities.

...South-Central States on D6-8/Monday-Wednesday...
Latest guidance continues to converge towards the more consistent
EC-AIFS with the evolution of the closed low off the southern CA
coast at 12Z Saturday. Similar to yesterday's EC-AIFS, this should
become an open but compact wave as it ejects across the southern
Rockies to the central Great Plains by Monday. The southern
influence of the wave may overspread the northern periphery of
western Gulf moisture, rendering at least low severe probabilities.

This wave may largely dampen into Tuesday with the more consistent
EC-AIFS indicating a mid-level ridge building from the Gulf into the
Mid-MS Valley, in advance of a large-scale trough in the West. The
EC-AIFS hints at another potential cutoff/closed low situation,
albeit farther east than the prior wave. With the GFS also
supporting this scenario, severe potential in this pattern might
remain marginal and confined to TX. This is in contrast to other
guidance suggesting a more progressive wave interacting with the
western Gulf moisture plume.

..Grams.. 11/12/2025

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ACUS48 KWNS 070805
SWOD48
SPC AC 070803

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0303 AM CDT Tue Oct 07 2025

Valid 101200Z - 151200Z

...DISCUSSION...
Upper ridging will persist over the Plains on Day 4/Fri. By Day 5 or
6/Sat or Sun, most medium-range guidance depicts an upper shortwave
trough ejecting from a larger-scale western U.S. trough across the
northern Plains. Surface high pressure over the eastern half of the
U.S. prior to this will limit boundary layer moisture and thus,
severe storm potential. However, by the end of the period, spread in
forecast guidance increases. The GFS shows a much more progressive
pattern, bringing an upper trough and cold front across much of the
Plains early next week, with little Gulf return flow to support
severe potential ahead of the front. The ECMWF is slower with the
eastward progression of the western U.S. trough, allowing for more
southerly return flow and increasing moisture across the Plains. If
this occurs, some severe potential could increase early next week.
However, given large uncertainty, predictability is too low.
Regardless, a pattern change toward early next week appears evident
for the Plains.

..Leitman.. 10/07/2025

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ACUS48 KWNS 080811
SWOD48
SPC AC 080810

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0310 AM CDT Wed Oct 08 2025

Valid 111200Z - 161200Z

...DISCUSSION...
An upper ridge over the Plains on Day 4/Sat will shift eastward
toward the Mid/Lower MS Valley on Day 5/Sun as an upper shortwave
trough over the Great Basin ejects northeast across the
northern/central Plains. Surface cyclogenesis will deepen across the
Dakotas as this occurs, and a cold front will sweep east across the northern/central Plains to the Upper Midwest by early Day 6/Mon.
Modest boundary layer moisture will be in place ahead of the cold
front, with severe potential likely limited by weak instability and
poor lapse rates.

Spread among medium range guidance increases by Days 6-8/Mon-Wed.
Some guidance maintains a upper trough/closed low over the eastern
U.S. early next week, maintaining an upper ridge over the central
U.S. while another trough deepens over the west. Other guidance is
more progressive, with the eastern trough moving offshore, allowing
the western trough will sweep east into the Plains by the end of the
period. Regardless of the exact evolution that unfolds, southerly
low-level flow across the Plains will allow for at least modest
moisture return into the southern/central Plains, increasing
thunderstorm potential. However, uncertainty precludes severe
probabilities at this time.

..Leitman.. 10/08/2025

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ACUS48 KWNS 220846
SWOD48
SPC AC 220845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0345 AM CDT Wed Oct 22 2025

Valid 251200Z - 301200Z

...DISCUSSION...
...D4/Sat-D5/Sun East TX/Lower MS Valley...
The upper low over the southern Plains will shift eastward this
weekend, gradually wakening as it moves over the lower MS Valley.
This should result in a rather nebulous surface pattern, with broad
low-level warm air advection expected over much of eastern TX and
the lower MS Valley. The environment will likely remain supportive
of scattered thunderstorms and isolated severe potential given
sufficient buoyancy and moderate flow aloft. However, confidence in
specific hazards or storm mode is low.

...D6/Monday Plains and MS Valley...
To the west of the departing upper low, a second Pacific trough will
move onshore over the Northwest late this weekend before
intensifying early next week. As the main trough and several
small-scale perturbations within enhanced westerly flow aloft cross
the Rockies, a surface low may develop over the Plains potentially
allowing for some northward return of moisture coincident with
increased vertical shear. This could support thunderstorms and some
severe risk across the eastern Plains and Mid/Lower MS Valley.

Model guidance remains highly varied on the evolution of this system
with the GEFS/GFS notable outliers in its intensity among other
solutions. Guidance has trended toward an overall less amplified and
more disjointed evolution, with persistent mid-level troughing over
the eastern US. This would likely suppress northward return moisture
and any potential warm sector over the Plains and Mid MS Valley.
Still, some severe risk remains possible over the southern Plains
and lower MS valley early next week given the increase in surface
moisture and flow aloft. However, the evolution and potential
hazards remains very uncertain.

..Lyons.. 10/22/2025

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ACUS48 KWNS 300802
SWOD48
SPC AC 300800

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 AM CDT Thu Oct 30 2025

Valid 021200Z - 071200Z

...DISCUSSION...
A deep mid/upper-level trough is forecast to move across the eastern
CONUS D4/Sunday into D5/Monday, as a strong upstream shortwave
trough digs into the Great Lakes region. Guidance varies regarding
the strength and timing of a mid/upper-level cyclone that may
develop within the southern portion of the initial large-scale
trough across parts of the Southeast. The strongest solutions (such
as the 30/00Z GFS) would support some strong-storm potential across
parts of FL into the Coastal Carolinas, but the current consensus is
for a persistent surface ridge to suppress inland low-level moisture
return and limit the organized-severe threat.

For D6/Tuesday and beyond, predictability decreases regarding the
evolution of the upper pattern, but most guidance continues to
depict a dearth of low-level moisture and instability across the
CONUS through the middle of next week.

..Dean.. 10/30/2025

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ACUS48 KWNS 130950
SWOD48
SPC AC 130949

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0349 AM CST Thu Nov 13 2025

Valid 161200Z - 211200Z

...DISCUSSION...
...South-Central States on D5-8/Monday-Thursday...
Bulk of guidance continues to follow the lead of the EC-AIFS with
the handling of a shortwave trough initially over the Southwest at
12Z Sunday. This compact wave should dampen as it crosses the
southern Rockies to the central Great Plains into Monday. The
peripheral southern influence of the wave may overspread the
northern periphery of a confined western Gulf moisture plume. While
5 percent severe probabilities are evident, this setup will likely
depend greatly on more precise timing of the trough ejection and
attendant surface cyclone placement for a 15 percent highlight.

The dampening of this wave will largely be in response to an upper
ridge building from the Gulf into the Midwest downstream of an
expansive trough becoming anchored over the Southwest. This may
yield expansion of the persistent western Gulf moisture plume in the South-Central States mid-week. Most guidance indicates an intense
mid-level jet may develop along the backside of this trough and
eventually curl through the base with the trough accelerating
eastward. Predictable timing of such a transition appears low given
the large spread across guidance, but the EC-AIFS and AIGFS are
consistent together in the 00Z run. This could yield an increasing
severe threat starting around Wednesday, which is supported by NSSL
GEFS ML version 1 probabilities peaking in this time frame.

..Grams.. 11/13/2025

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ACUS48 KWNS 090809
SWOD48
SPC AC 090807

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 AM CDT Thu Oct 09 2025

Valid 121200Z - 171200Z

...DISCUSSION...
An upper anticyclone is forecast to remain over TX for much of the
Day 4-8 period, with attendant upper ridging oscillating between the
Plains and the MS Valley. An upper shortwave trough over the Rockies
on Day 4/Sun will lift northeast across the northern Plains into
Canada, along with a deepening surface low. As this occurs, a cold
front will sweep east across the northern/central Plains and the
Upper Midwest through Day 5/Mon. Modest boundary layer moisture
ahead of the front will support at least weak instability and
thunderstorm potential. However, severe thunderstorm chances appear
low given richer boundary layer moisture will remain offset from
stronger shear/large-scale ascent.

Another upper shortwave trough is expected to move from the Rockies
into portions of the Plains late in the forecast period. As this
occurs, lee cyclogenesis is likely to occur, and southerly low-level
flow may transport modest Gulf moisture northward into the central
Plains to the MO Valley. Some increase in severe thunderstorm
potential could develop around Day 7 or 8/Wed or Thu, from the
southern/central Plains toward the MO Valley. However, confidence is
too low to include severe probabilities at this time given poor
run-to-run model consistency.

..Leitman.. 10/09/2025

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ACUS48 KWNS 160849
SWOD48
SPC AC 160847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Thu Oct 16 2025

Valid 191200Z - 241200Z

...DISCUSSION...
...Sunday/Day 4 and Monday/Day 5...
A large-scale mid-level trough and an associated cold front are
forecast to move through the Ohio and Tennessee Valleys on Sunday. Thunderstorms will likely be ongoing across the central Gulf Coast
states and Tennessee Valley at the start of the period. This
convection should have a negative impact on instability across the
much of the moist sector during the day. In areas that are not
impacted, weak instability is forecast to develop ahead of the front
from Georgia and the Carolinas into the central Appalachians. The
instability combined with strong large-scale ascent and moderate to
strong deep-layer shear will likely result in a severe threat. A
potential for wind damage and a few tornadoes will be possible. At
this time, uncertainty is substantial as to exactly where the
greatest severe potential will occur. As new runs come in, an
upgrade to Slight may be needed.

A mid-level low is forecast to move across the Northeast on Monday,
as the associated trough moves into the western Atlantic.
Thunderstorms with an isolated severe threat will be possible in
parts of southern New England during the late morning and early
afternoon before the front moves offshore.

...Tuesday/Day 6 to Thursday/Day 8...
On Tuesday and Wednesday, a mid-level trough is forecast to move
from the Mississippi Valley into the western Atlantic, as flow
becomes west-northwesterly across much of the eastern and northern
U.S. By Thursday, a mid-level low is forecast to develop in the
Desert Southwest. Thunderstorms will be possible ahead of this
system on Thursday across parts of the Four Corners region and
southern Rockies. However, uncertainty concerning the timing and
strength of this system is substantial at this extended range.

..Broyles.. 10/16/2025

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ACUS48 KWNS 230900
SWOD48
SPC AC 230859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Thu Oct 23 2025

Valid 261200Z - 311200Z

...DISCUSSION...
The upper trough over East TX is forecast to weaken as it moves over
the lower MS Valley late this weekend and into early next week.This
system will merge with several weaker perturbations over the eastern
US as a second trough and strong zonal jet are forecast to move out
of the Rockies and into the Plains. Mid-level ridging is expected to
develop across the Great Lakes and Southwest early next week. This
will likely result in blocked and split mid-level flow before deeper
troughing consolidates over the eastern half of the CONUS. As the
western ridging builds, flow aloft will trend more northwesterly,
suppressing overall amplification of the Plains trough.

Isolated severe potential remains possible D4/Sunday and D5/Monday
over parts of the southern Plains and the ArkLaMiss where remnant
moisture should intersect with enhanced flow aloft. However, poor
lapse rates and several rounds of proceeding storms lends low
confidence to specific hazards or spatial coverage.

Through the remainder of next week, broad eastern US troughing will
persist with strong northwesterly flow aloft over the western and
central US. A strong cold front will develop and sweep eastward
midweek, with surface high pressure developing in its wake. This
will likely keep substantial moisture return and resulting buoyancy
subdued for the foreseeable future.

..Lyons.. 10/23/2025

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ACUS48 KWNS 310841
SWOD48
SPC AC 310840

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0340 AM CDT Fri Oct 31 2025

Valid 031200Z - 081200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
West-northwesterly mid-level flow will be in place over the eastern
two-thirds of the nation during the early to mid-week. Through this
time, surface high pressure will remain dominant from the Great
Plains eastward into the eastern U.S. Further west, a mid-level
trough is forecast to move into California on Wednesday.
Thunderstorms will be possible along the coast of California as the
system moves inland.

...Thursday/Day 7 and Friday/Day 8...
The West Coast mid-level trough is forecast to move quickly eastward
across the Rockies on Thursday. Ahead of the system, isolated to
scattered thunderstorms appear most likely Thursday afternoon and
evening across parts of the southern and central Plains. A severe
threat will be possible with this activity. Ahead of the mid-level
trough, a severe threat may again develop over the Ozarks and mid
Mississippi Valley on Friday. The severe threat on Thursday and
Friday is expected to remain isolated, mainly due to relatively weak instability.

..Broyles.. 10/31/2025

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ACUS48 KWNS 070904
SWOD48
SPC AC 070902

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0302 AM CST Fri Nov 07 2025

Valid 101200Z - 151200Z

...DISCUSSION...
With a continental airmass intrusion across the entirety of the Gulf
and Atlantic Coasts by D4/Monday, severe and even thunder potential
should be negligible through mid-week. Modified return flow will
occur across the western Gulf and spread into the South-Central
States during mid to late week. But this will occur downstream of an
amplified upper ridge over the West, curtailing severe potential
through D8/Friday.

..Grams.. 11/07/2025

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ACUS48 KWNS 140808
SWOD48
SPC AC 140807

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0207 AM CST Fri Nov 14 2025

Valid 171200Z - 221200Z

...DISCUSSION...
A midlevel shortwave trough will dampen as it shifts east from the
central Plains toward the Mid-South in the Day 4-5/Mon-Tue time
period. Some enhanced westerly flow will overspread the region
nonetheless, and a weak surface low is forecast to track from KS/OK
toward the central or southern Appalachians through Tuesday night.
Ahead of the surface low and an attending cold front, modest Gulf
moisture return is forecast across the southern Plains into the
Lower MS Valley. Some strong to isolated severe thunderstorms could
develop across the Ozarks to the Mid-South vicinity Monday and
Tuesday, through confidence in 15 percent coverage is low given the
weakening midlevel trough and lack of a deepening surface cyclone.

During the Day 6-8 period, forecast model spread increases
considerably. However, a general trend indicating a deepening trough
across the West ejecting across the Plains toward the central U.S.
Thursday and Friday is apparent. Depending on the evolution of this
feature and any developing surface cyclone and attendant Gulf return
flow across the south-central U.S., an increase in severe
thunderstorm potential could develop. Large spread and poor
run-to-run consistency among various guidance precludes
probabilities at this time.

..Leitman.. 11/14/2025

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ACUS48 KWNS 100853
SWOD48
SPC AC 100851

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0351 AM CDT Fri Oct 10 2025

Valid 131200Z - 181200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
From Monday to Wednesday at mid-levels, a ridge is forecast to
remain over the central U.S., as a low moves into southern
California. Southwest flow is forecast over the Intermountain West
and Rockies. A chance for thunderstorms is expected to develop early
in the week ahead of the system, with a marginal severe threat
possible each afternoon across parts of Four Corners region. Any
severe threat should remain localized due to weak instability.

...Thursday/Day 7 and Friday/Day 8...
A shortwave trough is forecast to eject northeastward across the
central Rockies on Thursday, and into the northern Plains on Friday. Thunderstorms will be possible ahead of this trough, and in the
central Rockies Thursday afternoon. A severe threat could develop if
enough instability is realized ahead of the system. A secondary
trough is forecast to move across the Desert Southwest on Friday.
Isolated severe storms could occur ahead of this feature Friday
afternoon and evening, primarily in the southern Rockies. Although
this scenario on Thursday and Friday could pan out, the models
differ on the timing of the trough sequence. Also, instability is
forecast to be relatively weak. These factors suggest uncertainty,
and point to a more localized severe potential.

..Broyles.. 10/10/2025

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ACUS48 KWNS 170848
SWOD48
SPC AC 170847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Fri Oct 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...Northeast Day 4/Monday...
As the strong upper trough moves from the OH Valley and Appalachians
into the Northeast, low-end severe potential remains possible ahead
of the cold front D4/Monday over parts of New England. Confined to a
narrow warm sector with modest moisture but strong low-level wind
fields, shallow convection could support isolated damaging gusts
before the front moves offshore by mid afternoon.

...Rest of US...
As the strong eastern US trough and low move into the Atlantic early
next week, offshore flow should limit available moisture and
buoyancy for much of the CONUS. A mid-level low moving into the
Southwest and the southern Plains mid to late week could support
some thunderstorms activity toward the end of the forecast period.
However, uncertainty remains very high with model guidance
suggesting limited moisture return and poor overlap with stronger
vertical shear. Thus, predictability remains too low for severe
probabilities through the extended forecast period.

..Lyons.. 10/17/2025

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ACUS48 KWNS 240859
SWOD48
SPC AC 240857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Fri Oct 24 2025

Valid 271200Z - 011200Z

...DISCUSSION...
The upper trough over the Gulf Coast is forecast to continue
weakening before merging with an upper low over the Atlantic Coast
through early next week. Residual moisture and enhanced westerly
flow aloft could support some low-end severe risk D4/Monday over
parts of the Southeast. However, poor lapse rates and the potential
for multiple prior rounds of convection casts significant
uncertainty on severe potential.

Thereafter, the mid-level flow pattern will gradually amplify as
ridging develops over the Southwest. At the same time, broad eastern
US troughing is expected to form, intensifying northwesterly flow
aloft over the western and central US. A strong cold front will move
southward into the Gulf by midweek with strong surface high pressure
developing in its wake. Persistent eastern US troughing and high
pressure over the central US will favor cooler, drier and more
stable surface conditions for the foreseeable future.

..Lyons.. 10/24/2025

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ACUS48 KWNS 010840
SWOD48
SPC AC 010839

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0339 AM CDT Sat Nov 01 2025

Valid 041200Z - 091200Z

...DISCUSSION...
...Tuesday/Day 4 to Thursday/Day 6...
From Tuesday into Wednesday, a mid-level ridge is forecast to move
eastward into the central U.S., as a trough moves onto the West
Coast. As the trough moves inland Wednesday afternoon, thunderstorms
will be possible along the West Coast from northern California to
Washington. This trough is forecast to move quickly eastward into
the central Plains on Thursday. Isolated thunderstorms may develop
Thursday night ahead of the trough in parts of the Ozarks and mid
Mississippi Valley. The severe potential should remain limited due
to weak instability ahead of the trough.

...Friday/Day 7 and Saturday/Day 8...
As the mid-level trough progresses eastward into the Ohio Valley on
Friday, isolated to scattered thunderstorms will be possible during
the day. A marginal severe threat will be possible, if enough
instability can develop.

On Saturday, a large-scale mid-level trough is forecast to form over
the central U.S. Ahead of this feature, some low-level moisture is
expected to return into the lower to mid Mississippi Valley.
Although instability is forecast to be weak ahead of the system, an
isolated severe threat would be possible across parts of the Ohio
and Tennessee Valleys Saturday night. However, uncertainty is
substantial at this extended range.

..Broyles.. 11/01/2025

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ACUS48 KWNS 080836
SWOD48
SPC AC 080835

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0235 AM CST Sat Nov 08 2025

Valid 111200Z - 161200Z

...DISCUSSION...
Severe thunderstorm potential will be negligible through much of the
period in the wake of a continental airmass overspreading the Gulf
on D3/Monday. Modified return flow should slowly build across the
western Gulf mid to late week, with a maritime tropical airmass
approaching the northwest Gulf next weekend. Guidance still lacks
run-to-run continuity and timing spread is large, but consensus
indications are for an upper-level trough to progress into the
Southwest around next weekend. This could yield a return to severe
potential in the South-Central States after D8/Saturday.

..Grams.. 11/08/2025

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ACUS48 KWNS 150846
SWOD48
SPC AC 150845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0245 AM CST Sat Nov 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
Upper-level ridging over the Plains on Day 4/Tue will develop
eastward over the eastern third of the CONUS through Day 5/Wed as a
western upper trough slowly ejects over the Rockies and into the
Plains around Day 6/Thu. Gulf moisture will return northward across
the southern Plains and south-central states ahead of the ejecting
upper trough. Isolated strong to severe storms may be possible on
Wednesday across the southern Plains and Ozarks vicinity in a warm
advection regime ahead of the upper trough. By Day 6/Thu, the upper
trough should progress east across the Plains toward the Mississippi
Valley, with a surface cold front sweeping eastward as this occurs,
and some severe potential could accompany widespread thunderstorm
activity ahead of the front.

Confidence in coverage of severe storms Day 5-6/Wed-Thu is
uncertain. Large spread (and poor run-to-run consistency) exists
among forecast guidance. The GFS and ECMWF-AIFS are more similar
compared to the dynamical ECMWF, indicating a slower ejecting trough
and only modest surface cyclogenesis until late Thursday when the
low ejects northeast toward the Mid-MS Valley/Great Lakes.
Furthermore, while strong southwesterly flow will overspread
northward returning Gulf moisture across the Plains and
south-central states, forcing for ascent will be somewhat limited on
Wednesday as the trough ejects more slowly. As the trough ejects on
Thursday and a cold front becomes a focus for storm development, boundary-parallel deep-layer flow and a northeastward ejecting
cyclone may favor a more anafrontal, training convection/heavy
rainfall scenario. While severe potential certainly is in play for
Days 5-6/Wed-Thu, these uncertainties preclude 15 percent
probabilities at this time.

Beyond Day 6/Thu, model disparity increases substantially and
predictability is low.

..Leitman.. 11/15/2025

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ACUS48 KWNS 110848
SWOD48
SPC AC 110846

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Sat Oct 11 2025

Valid 141200Z - 191200Z

...DISCUSSION...
....Tuesday/Day 4 to Thursday/Day 6...
On Tuesday and Wednesday, a mid-level low is forecast to move
northeastward across the Intermountain West, as an associated jet
streak translates across the Four Corners region. Thunderstorms will
be possible well to the east of the system, along and near an axis
of instability in the southern Rockies Tuesday afternoon and
evening, where a marginal severe threat could develop. Moisture
advection is forecast Tuesday night into Wednesday across the
central and northern Plains, where a pocket of moderate instability
could develop by Wednesday afternoon. Scattered thunderstorms will
be possible across parts of the central and northern High Plains
Wednesday afternoon and evening, near and to the east of the exit
region of the mid-level jet. An isolated severe threat could
materialize in areas where instability becomes the strongest.

On Wednesday, a secondary trough is forecast to move into the
Rockies, as southwest mid-level flow remains in place over the Great
Plains. Thunderstorms are expected to develop within this southwest
flow Thursday afternoon and evening over parts Nebraska and the
Dakotas, where a marginal severe threat will be possible.

...Friday/Day 7 and Saturday/Day 8...
The large-scale mid-level trough is forecast to move over the
Rockies on Friday, as a ridge moves eastward into the Ohio and
Tennessee Valleys. Thunderstorms will be possible Friday into Friday
night between these two features, along and ahead of a cold front
from the upper Mississippi Valley southwestward into the central
Plains. Convective coverage is expected to expand on Saturday across
the Mississippi Valley, as the exit region of a large-scale
mid-level jet moves across the region. A severe threat will be
possible along a corridor of maximized low-level moisture and
instability from the Ozarks northward into the mid to upper
Mississippi Valley. Concerning the potential for a severe weather
event on Saturday, uncertainty is substantial mainly due to the
extended range and wide variance among the model solutions.

..Broyles.. 10/11/2025

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ACUS48 KWNS 180901
SWOD48
SPC AC 180859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Sat Oct 18 2025

Valid 211200Z - 261200Z

...DISCUSSION...
In the wake of the strong eastern US trough and cold front moving
offshore D3/Monday, a second upper low will deepen over the eastern
US through the first half of next week. As the low deepens,
persistent northwesterly flow aloft and surface high pressure will
build over the central US. Post-frontal offshore flow should limit
surface moisture/instability and resulting thunderstorm chances for
much of the CONUS through Wednesday.

Some thunderstorm potential may return D6/Thursday and D7/Friday as
a southern stream shortwave trough moves from the Southwest into the
southern Plains. Cooling temperatures aloft overspreading modest
moisture return over TX/OK could support some thunderstorm activity.
However, uncertainty on destabilization and stronger vertical shear
remains very high, thereby limiting severe predictability.

Additional thunderstorm chances may develop over the central US next
weekend as another Pacific trough approaches. But, model guidance
remains quite varied on the intensity/evolution as well as available
moisture ahead of this system. Thus, predictability remains too low
for severe probabilities through the extended forecast period.

..Lyons.. 10/18/2025

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ACUS48 KWNS 250818
SWOD48
SPC AC 250817

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0317 AM CDT Sat Oct 25 2025

Valid 281200Z - 021200Z

...DISCUSSION...
Severe storms appear unlikely over the CONUS through the extended
forecast period. An upper low is forecast to deepen over much of the
eastern US while ridging develops over the West. This will amplify
the overall pattern with strong northwesterly flow likely over much
of the central US. In response, a strong cold front and very deep
surface low will move offshore scouring available surface moisture
from the central US midweek next week. The persistent eastern US
troughing and high pressure in the wake of the cold front over the
central US will favor cooler, drier and more stable surface
conditions through the remainder of next week.

..Lyons.. 10/25/2025

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ACUS48 KWNS 020953
SWOD48
SPC AC 020951

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0351 AM CST Sun Nov 02 2025

Valid 051200Z - 101200Z

...DISCUSSION...
...Wednesday/Day 4 to Friday/Day 6...
A mid-level trough is forecast to move onto the West Coast on
Wednesday. As the trough moves inland, thunderstorm development will
be possible near the coast of northern California, Oregon and
Washington. The mid-level trough is forecast to move quickly
eastward into the central Plains on Thursday, and into the Ohio and
Tennessee Valleys on Friday. From Thursday afternoon into Friday,
thunderstorms will be possible from eastern parts of the central
Plains into the mid Mississippi Valley. Ahead of the trough,
low-level moisture return and the resultant instability is expected
to be somewhat limited, suggesting the severe potential will remain
minimal.

...Saturday/Day 7 and Sunday/Day 8...
On Saturday, a large-scale mid-level trough is forecast to quickly
take shape over the central U.S. Ahead of the trough, low-level
moisture is forecast to return northward into the Ark-La-Tex and mid Mississippi Valley, where thunderstorms will be possible Saturday
afternoon. Convective coverage is forecast to expand southeastward
into the Ohio and Tennessee Valley Saturday night. Model forecasts
suggest that moderate instability and strong deep-layer shear will
be in place, which would support a severe threat from Saturday
afternoon and evening. Concerning the potential for a severe weather
event, uncertainty is substantial. Some solutions suggest that the
favorable environment for severe will remain spatially focused into
a small area, and that a front could undercut the convection. For
this reason, will keep the forecast at "predictability too low".

On Sunday, the system is forecast to move eastward across the lower
to mid Mississippi Valley. Ahead of the trough, an isolated severe
threat will be possible across parts of the Southeast and southern
Atlantic Seaboard. However, uncertainty concerning the potential for
severe storms is considerable at this range.

..Broyles.. 11/02/2025

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ACUS48 KWNS 090848
SWOD48
SPC AC 090847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 AM CST Sun Nov 09 2025

Valid 121200Z - 171200Z

...DISCUSSION...
Modified return flow will slowly build across the western Gulf mid
to late week, with a maritime tropical airmass probably reaching
parts of the TX Gulf Coast next weekend. As mentioned by WPC's EPD,
run-to-run model variability remains high with a large amount of
spread in the potential evolution of a broad upper trough
approaching the West Coast on D5/Thursday. This is well illustrated
by the change in SPC-CSU GEFS-ML probabilistic guidance over the
past 24 hours for D7/Saturday -- from a mesoscale 5% area in the
Mid-MS Valley in yesterday's D8 to a full-latitude 5% from the Rio
Grande to the Great Lakes, along with broad 15% and 30% highlights
from parts of TX/LA to the Mid-MS Valley. While its parent 00Z GFS
appears conducive to severe, over what would likely be a subset of
these large highlights, this latest run lacks any semblance of
continuity. In addition, other models, such as the EC-AIFS suggest a
closed, cutoff low may just be in the process of moving onshore on
D7/Saturday, compared to the progressive, full-latitude trough over
the Great Plains in this GFS run. For this forecast, will upgrade to Predictability Too Low for D7/Saturday and extend into D8/Sunday for indications of possible severe, probably focused in the
South-Central States, within a low predictability pattern.

..Grams.. 11/09/2025

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ACUS48 KWNS 161001
SWOD48
SPC AC 160959

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CST Sun Nov 16 2025

Valid 191200Z - 241200Z

...DISCUSSION...
...D4/Wednesday - D5/Thursday...
An increase in severe potential remains evident across the
south-central CONUS from D4/Wednesday into D5/Thursday, but
uncertainty remains regarding many details and the overall magnitude
of the threat. Guidance is in somewhat better agreement regarding
the timing of the closed mid/upper-level low and attendant trough
that will move from the Southwest toward the south-central Plains
from late Wednesday into Thursday. Forcing may remain somewhat
nebulous during the day on Wednesday, but storms that may develop
late Tuesday night could continue into Wednesday morning, while
isolated diurnal development will be possible across the broader
warm sector. Deep-layer shear will be favorable for organized
storms, but low-level flow is generally forecast to be rather weak
until late Wednesday night.

As the approaching trough impinges upon rich boundary-layer moisture
and a reservoir of moderate buoyancy, storm development will become increasingly widespread Wednesday night into Thursday, along/ahead
of a north/south-oriented cold front that will move east across the southern/central Plains. Deep-layer shear will remain favorable for
storm organization, while low-level flow/shear should increase as a
surface low deepens and moves northeastward across the central
Plains. Some severe threat may expand from the southern Plains into
parts of the lower MO and mid MS Valleys with time on Thursday,
though buoyancy will become increasingly scant with northward
extent.

Given the late arrival of stronger large-scale ascent and low-level
mass response on Wednesday night, and the anticipated widespread
storm coverage on Thursday, the magnitude of available buoyancy and
the resulting severe threat remain uncertain. These uncertainties
appear to be reflected in the relatively broad and modest
probabilities from available calibrated guidance. However, given the
likelihood of a strong ejecting trough impinging upon anomalous
low-level moisture, severe probabilities will likely be needed in
subsequent outlooks.

...D6/Friday - D8/Sunday...
Predictability regarding the synoptic pattern becomes rather low by
late week into next weekend. Some severe threat could spread into
parts of the Southeast and Ohio Valley on Friday, though buoyancy
will become increasingly limited. Some guidance (such as the 16/00Z
ECMWF) depicts another deep trough moving across the southern Plains
next weekend, though spread regarding this potential system is quite
large within other extended-range guidance.

..Dean.. 11/16/2025

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ACUS48 KWNS 170908
SWOD48
SPC AC 170907

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 AM CST Mon Nov 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...Day 4/Thursday - Southern Plains to Mid-MS Valley...

An upper trough over the Four Corners vicinity will eject
east/northeast into the Plains on Thursday. Moderate southwesterly
deep-layer flow will overspread portions of OK/TX toward the Ozarks
as this occurs. Warm advection ahead of the trough, coincident with
a weakening southerly low-level jet, will result in widespread
showers and thunderstorms across the region early Thursday. This may
temper destabilization despite rich boundary layer moisture.
Meanwhile, a surface low will modestly deepen near the OK/KS border,
and a north-south oriented cold front draped across west TX will
develop eastward through the period, with a warm front extending
west-east across central MO/southern IL. These boundaries may focus
some risk for stronger storms within a weak to moderately unstable
airmass. However, the magnitude of the severe risk still remains
uncertain given potential for widespread and possibly heavy
rainfall, somewhat weak low-level flow, and the weakening of the
upper trough as it shifts east/northeast during the evening. Severe probabilities may become necessary is subsequent outlooks, but
uncertainty remains too high to include a 15 percent delineation at
this time.

...Day 5/Fri - Mid/Lower MS and OH/TN Valley vicinity...

The surface cold front will continue to develop east/southeast
across the region on Friday/Friday night. Some low-end severe
potential could persist given rich boundary layer moisture and at
least modest buoyancy ahead of the front. However, persistent
rainfall and a weakening upper trough with veering/boundary-parallel
deep-layer flow will likely limit storm intensity.

...Days 6-8/Sat-Mon...

Spread among forecast guidance increases late in the period and
forecast confidence is low. However, most guidance depicts some
version of an upper trough/low over the Southwest ejecting east
toward the Plains, but the differences in timing/intensity, etc
limit predictability. Some increase in severe potential could return
to portions of the southern Plains depending on how this potential
trough evolves and guidance trends will be monitored.

..Leitman.. 11/17/2025

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ACUS48 KWNS 120900
SWOD48
SPC AC 120858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Sun Oct 12 2025

Valid 151200Z - 201200Z

...DISCUSSION...
...Wednesday/Day 4 to Friday/Day 6...
A mid-level ridge is forecast to move slowly eastward from the
central and northern Plains on Wednesday to the Great Lakes and Ohio
Valley by Friday. During this time, a trough is forecast to move
eastward across the western half of the nation. Ahead of the trough
on Wednesday, isolated to scattered thunderstorms appear most likely
to develop from the southern Rockies into the northern Plains. An
isolated severe threat will be possible along and near the axis of
instability Wednesday afternoon and evening. The instability axis is
forecast to shift eastward into the central and northern Plains on
Thursday, and into the Upper Midwest on Friday. An isolated severe
threat will be possible along and near the instability axis on both
Thursday and Friday afternoon/evening.

...Saturday/Day 7 and Sunday/Day 8...
Low-level moisture advection is forecast to increase markedly on
Saturday as the trough moves into the Great Plains. By afternoon, an
axis of moderate instability could be in place from the southern
Plains into the Ozarks, with surface dewpoints in the 60s F.
Scattered to numerous thunderstorms may develop along and near this
axis of instability Saturday afternoon and evening. A severe threat
will be possible from Saturday into Saturday night as the trough
moves across the central U.S. A severe potential will also be
possible on Sunday, with the system forecast to move across the
Mississippi Valley.

Although there is model spread among the solutions, most have the
trough moving into the Great Plains on Saturday, with a moist and
unstable airmass located over the lower to mid Mississippi Valley.
This scenario seems plausible. However, the models do still have
significant variance on the timing and strength of the mid-level
system. For this reason, will not add a severe threat area at this
time.

..Broyles.. 10/12/2025

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ACUS48 KWNS 260845
SWOD48
SPC AC 260843

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CDT Sun Oct 26 2025

Valid 291200Z - 031200Z

...DISCUSSION...
Severe potential is low through the extended forecast period. A
strong upper trough and jet over the central US will merge with a
broad upper low over the eastern US midweek. At the same time,
ridging will develop over the West, as the flow pattern aloft
amplifies significantly. This will drive strong northwesterly flow
across the central CONUS. An associated cold front will sweep
through the central and eastern US before moving offshore D4/Wed. As
the front moves offshore, a deep coastal low is expected to develop
and could promote isolated thunderstorm activity along the East
Coast or south FL late this week and into the weekend. However, the
persistent eastern US troughing and strong surface high pressure
behind the cold front will favor much cooler, drier and more stable
surface conditions across the CONUS. Thus, thunderstorm chances are
low with little severe risk through the extended forecast period.

..Lyons.. 10/26/2025

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ACUS48 KWNS 190908
SWOD48
SPC AC 190906

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0306 AM CST Wed Nov 19 2025

Valid 221200Z - 271200Z

...DISCUSSION...
Most medium-range forecast guidance is consistent in developing an eastward-progressing upper low and attendant trough from the
Southwest into the southern/central Plains Day 4/Sat into Day 6/Mon.
Strong surface high pressure in the wake of an earlier cold frontal
passage in the Day 3/Fri period will extend from the southern Plains
into the Southeast, suppressing any deeper northward Gulf moisture
return until overnight Day 5/Sun when the upper trough ejects into
the High Plains. Some severe thunderstorm potential could develop
across southern into central TX late Sunday into Monday as a surface
cold front develops east across the southern Plains and stronger
southwesterly deep-layer flow overlaps returning Gulf moisture.
However, it is unclear if surface-based storms will develop given
the overnight nature of storm development and potential capping.
Severe probabilities may become necessary in later outlooks as
details regarding moisture return and timing of convection become
better resolved.

The upper trough will progress east/northeast across the Midwest and
Southeast late in the forecast period, with most guidance suggesting
broad, low-amplitude troughing developing across much of the CONUS
east of the Rockies by midweek. Some severe potential could persist
into the Lower MS Valley/Deep South vicinity on Day 7/Tue as upper
trough and surface low continue east, but large spread is present in medium-range guidance regarding the evolution of the surface low and
associated pre-frontal warm sector, resulting in low predictability.

..Leitman.. 11/19/2025

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