ACUS48 KWNS 040958
SWOD48
SPC AC 040956

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CST Wed Mar 04 2026

Valid 071200Z - 121200Z

...DISCUSSION...
...Saturday/Day 4 and Sunday/Day 5...
On Saturday at mid-levels, a shortwave trough is forecast to move
eastward across the north-central U.S., as flow remains
southwesterly from the southern Plains to the Eastern Seaboard. A
cold front is forecast to move southeastward across the southern
Plains, Ozarks, mid Mississippi Valley and Ohio Valley. Surface
dewpoints ahead of the front are forecast to be mostly in the 60s F
with pockets of moderate instability developing in the afternoon.
Scattered to numerous thunderstorms are expected to develop and move southeastward into the moist airmass. Although an isolated severe
threat will be likely in some areas, uncertainty is considerable
concerning the area with the greatest severe threat. The current
thinking is that the severe threat will be concentrated in two
areas, with one being from south-central Texas northeastward into
northern Louisiana, and a second being located in the Ohio Valley. A
15 percent area may need to be added in either of these two areas in
later outlooks.

On Sunday, a moist and unstable airmass is forecast along the
western Gulf Coast. Isolated storms associated with a marginal
severe threat could develop in the afternoon. Large-scale ascent
will be limited which should keep any severe potential localized.

...Monday/Day 6 to Wednesday/Day 8...
West-southwesterly mid-level flow is forecast to continue on Monday
across much of the central and eastern U.S. Low-level moisture
return is forecast to take place over the southern and central
Plains, where the models suggest moderate instability will be
possible by afternoon. As a low-level jet strengthens during the
afternoon and evening, isolated to scattered thunderstorms should
develop in areas that heat up sufficiently. A severe threat would be
possible. However, spatial uncertainty exists concerning where any
severe threat will be the greatest.

On Tuesday, model forecasts are in general agreement, moving an
upper-level trough northeastward into the southern High Plains. An
associated mid-level jet is forecast to eject northeastward ahead of
the system. Model forecasts suggest that the airmass ahead of the
trough will become moderately unstable by Tuesday afternoon. This
combined with strong large-scale ascent should support scattered
severe storms in the afternoon and evening. The favored severe
threat area is expected from parts of the southern and central
Plains eastward into the Ozarks.

On Wednesday, the upper-level trough is forecast to move across the south-central U.S., as a cold front advances eastward into the
Southeast. A severe threat may again develop Wednesday afternoon as
the airmass ahead of the front becomes unstable. However, there is
considerable model spread concerning the timing of features at this
extended range.

..Broyles.. 03/04/2026

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ACUS48 KWNS 050938
SWOD48
SPC AC 050936

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0336 AM CST Thu Mar 05 2026

Valid 081200Z - 131200Z

...DISCUSSION...
...Sunday/Day 4 and Monday/Day 5...
A moist airmass in the Gulf Coast region on Sunday will advect
northward into the east-central U.S. on Monday. Over the top of this
airmass, west-southwesterly mid-level flow will be in place.
Although large-scale ascent is forecast to be limited on both days,
isolated strong to marginally severe thunderstorms will be possible
in the afternoon in areas that heat up sufficiently. The greatest
potential for severe storms appears to be on Monday afternoon in the Ark-La-Tex, where moisture and low-level flow are currently forecast
to be maximized.

...Tuesday/Day 6 to Thursday/Day 8...
On Tuesday, model forecasts move an upper-level system across
northern Mexico, and retain southwesterly mid-level flow over much
of the south-central U.S. A moist and unstable airmass is forecast
over much of the southern and central Plains eastward into the lower
to mid Mississippi Valley. It appears that large-scale ascent
associated with the upper-level trough will gradually increase over
the southern and central Plains on Tuesday. In response, scattered thunderstorms should develop over parts of the moist sector Tuesday
afternoon and evening. Although model forecasts have slowed the
progression of the upper-level low, a belt of strong mid-level flow
is still forecast over the south-central U.S. on Tuesday. This
suggests that deep-layer shear will support severe thunderstorm
development, potentially across a broad area. The severe threat is
expected to continue from evening into the overnight period as the
upper-level trough approaches.

On Wednesday, the upper-level trough and an associated cold front is
forecast to move into the western Gulf Coast states. Ahead of the
system, a moist and unstable airmass appears likely by afternoon.
Thunderstorms that develop near and ahead of the front could have a
severe threat. However, there are still questions about the timing
of the trough and front. If model runs continue to suggest that the
system will move into the western Gulf Coast states on Wednesday,
then a risk area may need to be added. An isolated risk may also
develop on Wednesday northeastward ahead of the front in parts of
the Tennessee and Ohio Valleys.

On Thursday, the upper-level trough is forecast to move into the
eastern U.S., as the cold front moves offshore into the western
Atlantic. Thunderstorms with an isolated severe threat would be
possible along parts of the Eastern Seaboard before the front
passes. However, uncertainty at this extended range is considerable.

..Broyles.. 03/05/2026

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ACUS48 KWNS 060940
SWOD48
SPC AC 060938

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CST Fri Mar 06 2026

Valid 091200Z - 141200Z

...DISCUSSION...
...Day 4/Monday...

A weak upper shortwave impulse is expected to migrate across the
Ozarks/Lower MS Valley on Monday. This will support a narrow
corridor of enhanced westerly flow aloft atop a moistening boundary
layer. Isolated thunderstorms may develop across the ArkLaTex to
Lower MS Valley vicinity within the warm advection regime, and few
storms could become strong to locally severe. However, modest
forcing and otherwise lack of low-level focus precludes a 15 percent delineation.

...Day 5/Tuesday into Day 6/Wednesday...

An upper low and attendant shortwave trough over northwest Mexico is
forecast to eject eastward toward the southern High Plains on
Tuesday. At the same time, a broad upper trough within northern
stream flow will develop east from the northern Plains to the Upper
Midwest. As this occurs, a belt of enhanced southwesterly flow aloft
will overspread a large warm/moist sector from the southern Plains
to the Mid/Lower MS and Ohio Valleys. A complex surface pattern is
expected to emerge, influenced by the split-flow upper troughing
pattern. A baroclinic zone extending from OK the Mid-MS Valley area
will be one focus for severe thunderstorm potential. Meanwhile, lee
surface troughing across west TX and a developing dryline will be
another focus for severe storm development. While details remain
uncertain, these surface features, combined with strengthening
southwesterly flow overspreading a warm and unstable airmass, will
likely foster a broad area of severe thunderstorm potential from the
southern Plains into the Midwest.

As the upper troughs from Day 5/Tuesday continue east across the
southern Plains and Great Lakes on Day 6/Wednesday, a cold front is
expected to develop southeast across the Ohio Valley into east
Texas. Spread among forecast guidance increases during this time,
leading to more uncertainty. However, most guidance has some overlap
of favorable low-level moisture and instability with stronger
mid/upper level flow across portions of east TX into the Lower MS
valley. As a result, a 15 percent area has been delineated. This
area my need to shift/expand northeast with time depending on trends
in model guidance, but currently, it is uncertain if sufficient
destabilization will occur further northeast, precluding severe
probabilities into the TN/OH Valleys vicinity.

...Days 7-8/Thursday-Friday...

Predictability is low toward the end of the forecast period as
forecast model spread continues to increase. While it is plausible
some severe risk could persist into the Southeast on Day 7/Thursday
as the upper trough over the Lower MS Valley continues to migrate
east, uncertainty is too high to include probabilities at this time.

..Leitman.. 03/06/2026

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ACUS48 KWNS 061047
SWOD48
SPC AC 061046

Day 4-8 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0446 AM CST Fri Mar 06 2026

Valid 091200Z - 141200Z

CORRECTED FOR TEXT

...DISCUSSION...
...Day 4/Monday...

A weak upper shortwave impulse is expected to migrate across the
Ozarks/Lower MS Valley on Monday. This will support a narrow
corridor of enhanced westerly flow aloft atop a moistening boundary
layer. Isolated thunderstorms may develop across the ArkLaTex to
Lower MS Valley vicinity within the warm advection regime, and a few
storms could become strong to locally severe. However, modest
forcing and otherwise lack of low-level focus precludes a 15 percent delineation.

...Day 5/Tuesday into Day 6/Wednesday...

An upper low and attendant shortwave trough over northwest Mexico is
forecast to eject eastward toward the southern High Plains on
Tuesday. At the same time, a broad upper trough within northern
stream flow will develop east from the northern Plains to the Upper
Midwest. As this occurs, a belt of enhanced southwesterly flow aloft
will overspread a large warm/moist sector from the southern Plains
to the Mid/Lower MS and Ohio Valleys. A complex surface pattern is
expected to emerge, influenced by the split-flow upper troughing
pattern. A baroclinic zone extending from OK to the Mid-MS Valley
area will be one focus for severe thunderstorm potential. Meanwhile,
lee surface troughing across west TX and a developing dryline will
be another focus for severe storm development. While details remain
uncertain, these surface features, combined with strengthening
southwesterly flow overspreading a warm and unstable airmass, will
likely foster a broad area of severe thunderstorm potential from the
southern Plains into the Midwest.

As the upper troughs from Day 5/Tuesday continue east across the
southern Plains and Great Lakes on Day 6/Wednesday, a cold front is
expected to develop southeast across the Ohio Valley into east
Texas. Spread among forecast guidance increases during this time,
leading to more uncertainty. However, most guidance has some overlap
of favorable low-level moisture and instability with stronger
mid/upper level flow across portions of east TX into the Lower MS
Valley. As a result, a 15 percent area has been delineated. This
area may need to shift/expand northeast with time depending on
trends in model guidance, but currently, it is uncertain if
sufficient destabilization will occur further northeast, precluding
severe probabilities into the TN/OH Valleys vicinity.

...Days 7-8/Thursday-Friday...

Predictability is low toward the end of the forecast period as
forecast model spread continues to increase. While it is plausible
some severe risk could persist into the Southeast on Day 7/Thursday
as the upper trough over the Lower MS Valley continues to migrate
east, uncertainty is too high to include probabilities at this time.

..Leitman.. 03/06/2026

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ACUS48 KWNS 070836
SWOD48
SPC AC 070834

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 AM CST Sat Mar 07 2026

Valid 101200Z - 151200Z

...DISCUSSION...
...Days 4-5/Tue-Wed...

An active pattern with severe thunderstorm potential is expected
Tuesday and Wednesday from the southern Plains to the Mid/Lower MS
and OH Valleys. Medium range guidance is in fairly good agreement
during this time. Starting on Tuesday, an upper low over northern
Mexico will shift east/northeast, becoming an open wave as it begins
to merge with a northern stream upper trough developing southeast
across the northern/central Plains through early Wednesday. A belt
of strong southwesterly deep-layer flow will overspread a large warm
sector on Tuesday. Lee cyclogenesis is forecast across the
central/southern High Plains, along with a second surface low
developing over IA as the northern stream upper trough approaches.
This setup will allow for a sharpening dryline/Pacific front across
the southern Plains, while a cold front develops southeast into the
MO/Mid-MS Valley overnight. Strong ascent should focus thunderstorm
development across the warm sector ahead of these surface boundaries
within a strongly sheared environment, and potentially widespread
severe thunderstorm activity is possible.

The large-scale upper trough and attendant surface cold front will
continue to progress eastward on Wednesday. Uncertainty does
increase, especially with north and east extent of severe potential.
How far east convection develops on Tuesday and how much downstream destabilization occurs is somewhat unclear. Nevertheless, a
deepening surface cyclone is forecast to develop northeast from the
Great Lakes into Ontario and Quebec, while strong deep layer
southwesterly flow overspreads a moist warm sector ahead of the
surface front. This should set the stage for at least isolated to
scattered severe thunderstorm potential along the length of the cold
front through Wednesday evening.

Given uncertainties mentioned above, these areas are likely to be
adjusted in coming days as details become better resolved, but the
overall pattern should support a couple of active severe weather
days over a broad area.

...Day 6/Thu...

Uncertainty increases by Thursday as spread among medium range
guidance increases quite a bit with respect to the evolution/timing
of the upper trough. Some severe potential could persist/develop
across the Mid-Atlantic region, but predictability is too low to
include a 15 percent delineation at this time.

Beyond Thursday, severe thunderstorm potential will likely be low as
the upper pattern become lower amplitude and stronger westerly flow
remains confined to the northern tier of the U.S., along with Gulf
moisture largely remaining offshore behind the cold frontal passage.

..Leitman.. 03/07/2026

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ACUS48 KWNS 080916
SWOD48
SPC AC 080914

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0414 AM CDT Sun Mar 08 2026

Valid 111200Z - 161200Z

...DISCUSSION...
...Day 4/Wed...

A large-scale upper trough will continue to shift east across the
central U.S. on Wednesday, becoming oriented from the Upper Great
Lakes to the central Gulf coast vicinity by Thursday morning. An
embedded shortwave within the base of this trough will move from the
southern Plains to the Deep South, while the northern branch of the
trough moves across the Midwest. Strong deep-layer southwesterly
flow will overspread a broad warm sector across much of the Midwest
and southern U.S. Meanwhile, a cold front will develop southeast
through the period, tracking across much of the Mid/Lower MS, OH and
TN Valleys.

Uncertainty exists regarding where convection may be ongoing
Wednesday morning, and some potential exists for widespread
thunderstorm activity across parts of the Midwest. As a result, it
is uncertain how far north quality thermodynamics will exist.
Nevertheless, it appears likely at least some severe risk will exist
across the Ohio Valley given favorable boundary-layer moisture and
impressive vertical shear profiles. Further southwest toward the
Lower MS Valley into the Deep South vicinity, morning convection may
be more limited compared to further north, allowing for more
extensive destabilization ahead of the surging cold front. A
mixed-mode of supercells ahead of the cold front, and an organized
line of storms along the cold front will be possible across this
area.

As mesoscale details become better resolved in the coming days, the
severe area for Wednesday is likely to shift some. However, the
overall pattern suggests a broad area of severe thunderstorm
potential is probable on Wednesday.

...Day 5/Thu...

Some severe thunderstorm potential could persist into portions of
the Mid-Atlantic and Southeast. However, uncertainty is fairly high
given this potential will depend on evolution of convection on Day
4/Wed, which could be quite extensive and outpace the surface front
Wednesday night into early Day 5/Thu. As such, predictability is
low.

...Days 6-8/Fri-Sun...

Severe thunderstorm potential appears low during the weekend as
broad upper troughing persists across the central/eastern U.S.

..Leitman.. 03/08/2026

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ACUS48 KWNS 090833
SWOD48
SPC AC 090831

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CDT Mon Mar 09 2026

Valid 121200Z - 171200Z

...DISCUSSION...
...Day 4/Thu...

Some low-end severe thunderstorm risk could persist into Day 4/Thu
across portions of the Southeast as an upper trough pivots toward
the Atlantic coast in tandem with an eastward-advancing surface cold
front. Ahead of the front, a moist airmass will be in place from
GA/FL northeast toward southeast VA. Convection will likely be
ongoing Thursday morning, and persistent warm advection will result
in widespread cloudiness. This will limit destabilization and lapse
rates are expected to remain modest. Overall, severe potential
appears less than 15 percent.

...Days 5-8/Fri-Mon...

Severe thunderstorm potential appears low Friday and Saturday as a
prior cold frontal passage into the Gulf leaves a dearth of boundary
layer moisture in its wake. Another upper trough is expected to
deepen over the Plains and the eastern U.S. late in the period. Some
moisture return may occur ahead of this feature before another cold
front develops southeast across the eastern half of the CONUS. This
could bring some increasing thunderstorm potential to parts of the south-central or southeast U.S., however, at this time any better
moisture return looks displaced to the south of stronger flow aloft.

..Leitman.. 03/09/2026

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ACUS48 KWNS 100748
SWOD48
SPC AC 100747

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 AM CDT Tue Mar 10 2026

Valid 131200Z - 181200Z

...DISCUSSION...
Severe thunderstorm potential will remain low on Days 4-5/Fri-Sat as
a cold frontal passage and surface high pressure over the central
U.S. leave a dry/stable airmass across much of the CONUS east of the
Rockies.

On Saturday, lower-amplitude, quasi-zonal flow over much of the U.S.
will amplify as a shortwave upper trough deepens over the Rockies
and emerges over the High Plains by Day 6/Sunday morning. As this
occurs, modest Gulf moisture will return northward across east TX
into the Mid-South. A strong surface low is forecast to move across
the Upper Midwest on Sunday as the upper trough continues to dig and
shift east into the Midwest. This will bring a cold front southeast
across portions of the Plains and Midwest. Some severe potential
could develop across central portions of the U.S. on Day 6/Sunday as
the cold front sweeps eastward, but confidence is low given a lack
of deeper moisture return overlapping with stronger shear across the
Midwest.

As the upper trough and surface cold front continue east on Day
7/Monday, some low-end severe potential could possibly develop
across the Mid-Atlantic to the Southeast, but confidence is low
given similar concerns to those on Day 6/Sunday. With this system
moving offshore by the end of the period, severe potential appears
low on Day 8/Tuesday.

..Leitman.. 03/10/2026

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ACUS48 KWNS 110754
SWOD48
SPC AC 110752

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0252 AM CDT Wed Mar 11 2026

Valid 141200Z - 191200Z

...DISCUSSION...
...Days 4-6/Sat-Mon...

An upper trough will begin to deepen as it moves over the northern
Rockies and into the northern/central High Plains on
Saturday/Saturday night. As this occurs, a lee cyclone will deepen
as it shifts east across the central Plains toward the MO Valley by
early Sunday. Modified Gulf moisture will return northward in
response to increasing southerly low-level flow ahead of the surface
cyclone and attendant cold front. Medium range guidance is in fairly
good agreement that any deeper/higher quality moisture will remain
confined to east TX and the immediate Gulf coast on Sunday. With
northward extent into the Mid-South, Mid-MS and Lower OH, and TN
Valleys, 50s F dewpoints appear more likely. The upper trough will
intensify and shift east across the Midwest and south-central U.S.
on Sunday, but stronger flow aloft will remain displaced from better
quality moisture return. While some severe potential could develop
from east TX into the Lower OH/TN Valleys as a strong cold front
tracks east across the central U.S. on Sunday, probabilities appear
less than 15 percent at this time.

This system will shift east across the eastern U.S. on Monday,
though any severe potential along the East Coast appears low at this
time as the primary forcing for ascent lags behind the surface
front.

...Days 7-8/Tue-Wed...

An amplified upper ridge will build across the western U.S. during
the end of Tuesday and Wednesday while upper troughing persists
across the East. Surface high pressure and the prior cold frontal
passage into the Gulf will leave a stable and dry airmass in place,
precluding severe potential.

..Leitman.. 03/11/2026

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ACUS48 KWNS 120817
SWOD48
SPC AC 120815

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0315 AM CDT Thu Mar 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...
...Day 4/Sunday - ArkLaTex/Lower MS Valley into the Middle MS/Lower
OH Valleys...

An intense upper trough will deepen over the Plains and shift east
to the MS Valley on Sunday. From late afternoon into the nighttime
hours, an 80-100 kt jet streak will develop within the base of the
trough and overspread portions of the region. At the surface, an
already strong cyclone will deepen further as it moves from the
Lower MO Valley to the Lower Great Lakes vicinity. As this occurs, a
strong cold front will sweep eastward across the southern Plains and
much of the Midwest and Southern U.S., becoming oriented from Ohio
to the FL Panhandle by Monday morning.

While strengthening southerly low-level flow will develop ahead of
the front, stronger Gulf moisture return will be confined to TX and
the Lower MS Valley vicinity, with mainly 50s dewpoints expected
with northward extent across the Middle MS and OH Valley regions.
Furthermore, capping is expected ahead of the cold front,
potentially limiting warm sector convection. Nevertheless, modest
moisture and steepening midlevel lapse rates will support at least
weak destabilization very near the cold front. A narrow line of
strongly-forced convection is expected to develop along the cold
front and move across portions of OK/TX into the Middle/Lower MS and
Lower OH/TN Valley regions. Given intense deep-layer flow near and
just behind the cold front, strong/damaging wind potential will
exist within a modest instability/high shear environment. A 15
percent severe delineation has been included from the ArkLaTex into
the Mid-South/Lower MS Valley vicinity. Depending on low-level moisture/instability trends, this area may need to be expanded north
and east into a larger portion of the Middle MS/Lower OH/TN Valley
vicinity in subsequent outlooks.

...Day 5/Monday - Southeast to Mid-Atlantic...

Severe thunderstorm potential will likely continue into Monday as
the intense upper trough continues to migrate east from the MS
Valley toward the Eastern Seaboard. Intense deep-layer southwesterly
flow will overspread portions of the Southeast to the Mid-Atlantic.
Meanwhile, 60s F dewpoints will extend from southeast GA northward
through the Mid-Atlantic ahead of a sharp cold front. Pre-frontal
surface troughing across the VA/NC Piedmont also will support
backing low-level winds, leading to enhanced low-level shear.
Depending on how much cloud cover and warm advection precipitation
occurs ahead of the cold front, stronger destabilization may be
inhibited. Nevertheless, at least weak instability is forecast ahead
of a strongly forced line of convection along the eastward-advancing
cold front. This activity alone could produce a swath of strong to
severe wind gusts. A more conditional risk of supercells across the
warm sector exists across eastern VA/NC, but this is more uncertain.
Given damaging wind potential with the strongly forced linear
convection, a 15 percent severe delineation has been added for
portions of the region.

...Days 6-8/Tuesday-Thursday...

Severe thunderstorm potential will be low Tuesday through Thursday
as strong surface high pressure builds in the wake of the earlier
cold frontal passage. A dry/stable airmass will prevail as Gulf
moisture remains well offshore.

..Leitman.. 03/12/2026

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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 Fri Mar 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...
Significant severe winds and the potential for a few tornadoes will
develop on Monday over parts of the Carolinas and Mid Atlantic.

Models are in good agreement with the large scale pattern on
Monday/D4, depicting a deep upper trough moving out of the
Mississippi Valley and ejecting in negative-tilt fashion across the
Mid Atlantic and into to the Northeast.

Given the antecedent upper ridging on the previous day, low-level
southerly winds will help to moisten the air mass well ahead of an
approaching cold front. By 12Z Monday, 60s F dewpoints will already
extend from northern GA across the Piedmont and into southeast VA,
and this plume of moisture will rapidly spread north with near 60 F
dewpoints into southeast PA by 00Z.

There appears to be two regimes for severe potential on Monday.
First, up to 1000 J/kg MUCAPE may develop well ahead of the
approaching cold front, and there is some indication that scattered
convection may occur across the warm sector from mid to late
afternoon. If this occurs, supercells would be most likely, with
potential for a few tornadoes from the Carolinas into eastern VA.

Models also indicate an elongated pressure fall/rise couplet, which
when combined with 50-70 kt 850 mb winds and extreme low-level
shear, could easily result in a QLCS along the cold front with
corridors of significant damaging winds and embedded tornado risk.

Beyond Monday/D4, stable air behind this system will likely preclude
any severe threat through Friday/D8.

..Jewell.. 03/13/2026

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ACUS48 KWNS 131953
SWOD48
SPC AC 131951

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Fri Mar 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...
Significant severe winds and the potential for a few tornadoes will
develop on Monday over parts of the Carolinas and Mid Atlantic.

Models are in good agreement with the large scale pattern on
Monday/D4, depicting a deep upper trough moving out of the
Mississippi Valley and ejecting in negative-tilt fashion across the
Mid Atlantic and into to the Northeast.

Given the antecedent upper ridging on the previous day, low-level
southerly winds will help to moisten the air mass well ahead of an
approaching cold front. By 12Z Monday, 60s F dewpoints will already
extend from northern GA across the Piedmont and into southeast VA,
and this plume of moisture will rapidly spread north with near 60 F
dewpoints into southeast PA by 00Z.

There appears to be two regimes for severe potential on Monday.
First, up to 1000 J/kg MUCAPE may develop well ahead of the
approaching cold front, and there is some indication that scattered
convection may occur across the warm sector from mid to late
afternoon. If this occurs, supercells would be most likely, with
potential for a few tornadoes from the Carolinas into eastern VA.

Models also indicate an elongated pressure fall/rise couplet, which
when combined with 50-70 kt 850 mb winds and extreme low-level
shear, could easily result in a QLCS along the cold front with
corridors of significant damaging winds and embedded tornado risk.

Beyond Monday/D4, stable air behind this system will likely preclude
any severe threat through Friday/D8.

..Jewell.. 03/13/2026

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ACUS48 KWNS 132006
SWOD48
SPC AC 132004

Day 4-8 Convective Outlook AMEND 1
NWS Storm Prediction Center Norman OK
0304 PM CDT Fri Mar 13 2026

Valid 161200Z - 211200Z

AMENDED TO EXPAND D4/MONDAY THREAT AREAS

...DISCUSSION...
...Updated discussion for D4...
The majority of deterministic and ensemble model guidance agree on a
deep midlevel trough and associated cold front that will move
eastward across the Appalachians and to the Atlantic coast by
Tuesday morning. Severe storms could be ongoing at the beginning of
the period along the northeast Gulf coast into GA. The warm sector, characterized by boundary-layer dewpoints in the 60s, will expand
northward (generally east of the Appalachians) through the day as
far north as PA. Though clouds could limit downstream surface
heating somewhat, very strong wind profiles and focused forcing for
ascent will favor a continuation of convection along the front, as
well as pre-frontal convection, with the potential to produce
relatively widespread damaging winds and several tornadoes.

...Previous discussion below...
Significant severe winds and the potential for a few tornadoes will
develop on Monday over parts of the Carolinas and Mid Atlantic.

Models are in good agreement with the large scale pattern on
Monday/D4, depicting a deep upper trough moving out of the
Mississippi Valley and ejecting in negative-tilt fashion across the
Mid Atlantic and into to the Northeast.

Given the antecedent upper ridging on the previous day, low-level
southerly winds will help to moisten the air mass well ahead of an
approaching cold front. By 12Z Monday, 60s F dewpoints will already
extend from northern GA across the Piedmont and into southeast VA,
and this plume of moisture will rapidly spread north with near 60 F
dewpoints into southeast PA by 00Z.

There appears to be two regimes for severe potential on Monday.
First, up to 1000 J/kg MUCAPE may develop well ahead of the
approaching cold front, and there is some indication that scattered
convection may occur across the warm sector from mid to late
afternoon. If this occurs, supercells would be most likely, with
potential for a few tornadoes from the Carolinas into eastern VA.

Models also indicate an elongated pressure fall/rise couplet, which
when combined with 50-70 kt 850 mb winds and extreme low-level
shear, could easily result in a QLCS along the cold front with
corridors of significant damaging winds and embedded tornado risk.

Beyond Monday/D4, stable air behind this system will likely preclude
any severe threat through Friday/D8.

..Thompson.. 03/13/2026

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ACUS48 KWNS 140851
SWOD48
SPC AC 140850

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0350 AM CDT Sat Mar 14 2026

Valid 171200Z - 221200Z

...DISCUSSION...
On Tuesday/D4, a large upper trough will move across the Northeast,
though the associated surface cold front will already be well
offshore the East Coast with high pressure over land. Behind this
upper trough, models indicate a large upper ridge will be situated
over the Southwest for several days, with a northwest flow pattern
across the Plains. Given this pattern, minimal appreciable moisture
return is expected over the CONUS, and severe storms appear unlikely
through Saturday/D8.

..Jewell.. 03/14/2026

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ACUS48 KWNS 150852
SWOD48
SPC AC 150850

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0350 AM CDT Sun Mar 15 2026

Valid 181200Z - 231200Z

...DISCUSSION...
Severe storms appear unlikely across the CONUS for the D4-8 period,
as an upper ridge holds over the Southwest with a mean upper trough
over the East. This pattern will keep a surface high over much of
the east/southeast CONUS, with northerly winds over the Gulf Of
America for much of the period.

Models do indicate the upper ridge over the Southwest may weaken
into the Sat/D7 and Sun/D8 time frame, with perhaps the pattern
trending toward zonal. Even so, potential for any significant
instability to develop over land remains minimal.

..Jewell.. 03/15/2026

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ACUS48 KWNS 160648
SWOD48
SPC AC 160646

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0146 AM CDT Mon Mar 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
A northwest flow regime will persist across the Plains through
Saturday/D6 as an upper high holds over the southwestern states. The
ridge is expected to break down late D6 through the remainder of the
period into Monday/D8, as a strong wave moves southeastward into the
Great Lakes, and a weaker wave potentially moves into the Great
Basin/Four Corners states on Sunday/D7. This overall pattern will
maintain relatively stable conditions over most of the CONUS, with
high pressure over the southeastern states including the Gulf of
America. Further, as the stronger wave potentially moves across the
Great Lakes and into the Northeast, a reinforcing cold front is
likely to plunge south over much of the central and eastern states
into the D7/D8 time frame. While limited moisture may precede this
cold front, overall potential for destabilization appears to be
minimal.

..Jewell.. 03/16/2026

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ACUS48 KWNS 170614
SWOD48
SPC AC 170612

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0112 AM CDT Tue Mar 17 2026

Valid 201200Z - 251200Z

...DISCUSSION...
An upper ridge will hold over the Southwest from Fri/D4 into Sat/D5,
but will begin to flatten as a progressive, low-amplitude wave moves
into the far northern Rockies and Plains. This feature is then
forecast to amplify across the Great Lakes and Northeast during the
Sun/D6 to Tue/D8 period, while an upper ridge possibly re-builds
over the Southwest. However, predictability becomes low for that
pattern change.

In association with the northern wave, low pressure with a trailing
cold front may develop from the Plains to the Mid Atlantic from
Sun/D6 into Mon/D7. Given the antecedent dry conditions, only
marginal moisture return and destabilization are expected. While
this may support scattered thunderstorms across the Ohio Valley
region on Sunday/D6, substantial severe weather is not anticipated.

Behind that system, a reinforcing high will likely spread south
across the Plains and much of the East, resulting in stable
conditions.

..Jewell.. 03/17/2026

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ACUS48 KWNS 180719
SWOD48
SPC AC 180717

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 AM CDT Wed Mar 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
An upper ridge is forecast to break down across the Southwest late
Saturday/D4 into Sunday/D5, with a weak wave embedded in the
northwesterly flow regime aloft. During the same time, a stronger
but low-amplitude feature will move rapidly east/southeast along the
Canadian border, across the Great Lakes and into the Northeast.

In association with the northern/Great Lakes disturbance, a cold
front is forecast to push south into the Plains on Sunday/D5,
extending into the OH Valley by late in the day. This front will
interact with marginal moisture return across the Mid MS/OH Valleys,
and continue into the Southeast on Monday/D6. This front is forecast
to be roughly parallel to the upper flow, and would likely undercut thunderstorms that develop along it. MUCAPE on the order of 500-1000
J/kg seems reasonable, which will support marginal severe at best.

For the latter days of the period, the forecast becomes less
predictable, however, models on a run to run basis appear to be
trending toward higher heights/possible ridging over the Southwest,
with little to no threat of severe storms.

..Jewell.. 03/18/2026

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ACUS48 KWNS 190901
SWOD48
SPC AC 190859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Thu Mar 19 2026

Valid 221200Z - 271200Z

...DISCUSSION...
On Sunday/D4, thunderstorms will be possible over parts of the OH
Valley into the Appalachians, and perhaps as far south as the TN
Valley, as an upper trough amplifies across the upper MS Valley and
into the Great Lakes. A cold front is forecast to extend
southwestward from a low over NY/PA, with perhaps lower 60s F
dewpoints and MUCAPE on the order of 500-1500 J/kg possible. Models
appear to have a wide range of instability values for Sunday, and as
such predictability is low. However, there is at least some
potential for strong to perhaps a few severe storms over the mid to
upper OH Valley. The most likely scenario is for a marginal setup
given the northwest flow pattern and modest-moisture-content warm
sector.

This front will push south toward the Gulf Coast on Monday/D5, with
high pressure building in to the north. The upper trough will move
across the Northeast on Monday, with another possibly amplifying
across the Great Lakes/Northeast Tuesday/D6 into Wednesday/D7. As
this occurs, an upper ridge is likely to exist across the Southwest,
with little overall severe potential for those days.

..Jewell.. 03/19/2026

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