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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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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