ACUS48 KWNS 010829
SWOD48
SPC AC 010827

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0327 AM CDT Wed Apr 01 2026

Valid 041200Z - 091200Z

...DISCUSSION...
Some degree of severe thunderstorm potential is expected to persist
through the upcoming weekend across portions of the Great Lakes/OH
Valley and possibly across the Mid-Atlantic. Heading into next week,
a combination of building surface high pressure behind a synoptic
cold front and the re-establishment of an upper ridge over the West
will limit severe weather chances.

...D4/Saturday - Great Lakes/OH Valley...
An upper wave and attendant surface low are forecast to quickly
translate from the Plains into the Great Lakes region late Friday
through Saturday. Moisture return immediately ahead of a trailing
cold front will likely support some degree of destabilization
Saturday afternoon across the Great Lakes/OH Valley; however,
long-range ensemble guidance does not show high probability in surface/mixed-layer buoyancy values exceeding 1000 J/kg.
Nonetheless, strong flow within the lowest 1-2 km will likely
support a severe wind threat with any convection that can become
sufficiently intense. While some severe risk is anticipated, the
combination of a modest thermodynamic environment and disagreement
regarding the timing/progression of the front through peak heating
precludes risk probabilities.

...D5/Sunday - Mid-Atlantic...
The synoptic cold front is forecast to push off the East Coast by
late Sunday, though long-range guidance shows disagreement regarding
the timing of the front. Slower solutions, such as the 00z ECMWF,
suggest that the frontal passage may occur during the afternoon
hours when diurnal destabilization will be greatest. Strong
low-level flow coupled with robust broad-scale ascent ahead of the
primary upper wave may support a band of strong to severe
thunderstorms. However, the general consensus among guidance at this
time is that this scenario is likely the outlier solution.

..Moore.. 04/01/2026

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ACUS48 KWNS 020835
SWOD48
SPC AC 020833

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0333 AM CDT Thu Apr 02 2026

Valid 051200Z - 101200Z

...DISCUSSION...
Severe weather potential will be limited for late weekend and into
the upcoming work week based on trends in latest guidance. A strong
synoptic cold front is forecast to push from the Appalachians and
lower MS Valley east/southeastward towards the East Coast and
northern Gulf through the day Sunday. While some severe threat may
materialize across the Carolinas and Mid-Atlantic Sunday afternoon,
it will be conditional on favorable timing of the frontal passage
with the diurnal heating maximum. The frontal passage will shunt
appreciable low-level moisture offshore by early Monday. Building
surface high pressure over the central to eastern CONUS through
early week will maintain dry and stable conditions east of the
Rockies. Additionally, the amplification of an upper ridge over the
West will limit thunderstorm chances across the Intermountain West.
This synoptic regime will limit moisture return back into the Plains
with most guidance suggesting that appreciable moisture return (55+
dewpoints) may not return to the Plains until the D8/Thursday time
frame. Consequently, the potential for severe convection will be
limited through at least the middle of the upcoming week.

..Moore.. 04/02/2026

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ACUS48 KWNS 030822
SWOD48
SPC AC 030821

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0321 AM CDT Fri Apr 03 2026

Valid 061200Z - 111200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
From Monday to Wednesday, a relatively dry and cool airmass is
forecast to settle in across the continental U.S. For this reason,
thunderstorm potential will be low over most of the nation.

...Thursday/Day 7 to Friday/Day 8...
A large area of surface high pressure is forecast to move eastward
in the western Atlantic by Thursday, as moisture return takes place
into the south-central states. Scattered thunderstorm development
will be possible during the day from the southern and central Plains
eastward into the lower to mid Mississippi Valley. A chance for
thunderstorms will continue into Friday over the same general area
as moisture advection continues. An isolated severe threat will be
possible each afternoon and evening, but the confidence in the
spatial distribution regarding any potential threat is low at this
time.

..Broyles.. 04/03/2026

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ACUS48 KWNS 040846
SWOD48
SPC AC 040844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Sat Apr 04 2026

Valid 071200Z - 121200Z

...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5...
A large area of surface high pressure will settle in across the
continental U.S. on Tuesday and Wednesday. The associated dry and
cool airmass will limit thunderstorm potential in most areas.

...Thursday/Day 6 to Saturday/Day 8...
On Thursday, a cold front is forecast to move southward into the
central Plains and stall, as moisture advection takes place to the
south of the front over much of the southern Plains. A dryline is
forecast to setup over west Texas Thursday afternoon. Thunderstorm
development will be likely along parts of the front and to the east
of the dryline. An isolated severe threat will be possible in the
afternoon and evening. Models differ considerably on the
distribution of instability, with some suggesting that instability
will remain relatively weak. This would keep any severe threat
marginal in most areas.

On Friday and Saturday, a moist and unstable airmass is forecast to
be in place over the southern half of Texas, as a shortwave trough
moves northeastward across the region. Lift associated with this
feature would support scattered thunderstorm development. The
greatest severe potential both Friday and Saturday appears to be
across south-central Texas, where the models have moderate
deep-layer shear and sufficient instability. At this extended range, uncertainty concerning magnitude and spacing is substantial.

..Broyles.. 04/04/2026

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ACUS48 KWNS 050850
SWOD48
SPC AC 050848

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Sun Apr 05 2026

Valid 081200Z - 131200Z

...DISCUSSION...
...Wednesday/Day 4 and Thursday/Day 5...
From Wednesday into Thursday, an upper-level trough will move from
the High Plains into the Great Lakes, as a large area of surface
high pressure moves across the eastern U.S. Along the western edge
of this feature on Thursday, low-level moisture advection is
forecast from the southern and central Plains into the lower to mid
Mississippi Valley. Within this returning airmass, isolated to
scattered thunderstorms will be possible Thursday afternoon and
evening. The best chance for severe storms would be across parts of
the central Plains, as the low-level jet ramps up in the evening.
Uncertainty exists concerning the magnitude of any potential severe
threat.

...Friday/Day 6 to Sunday/Day 8...
Moisture advection is forecast to continue on Friday over the
southern Plains and Ark-La-Tex, as surface dewpoints increase into
the 60s F. A slow-moving cold front is forecast to stall in the
central Plains, which would be a focus for thunderstorm development.
Isolated to scattered storms are also expected on Friday along and
to the east of a dryline in the southern High Plains. An isolated
severe threat would be possible in areas that sufficiently
destabilize. The potential for severe storms should continue into
Saturday and Sunday over the southern and central Plains, as an
upper-level trough moves across the region. At this time, model
spread is substantial concerning the magnitude and spatial
distribution of instability. The models also vary widely on the
timing and amplitude of the shortwave trough. For these reasons,
will hold off introducing a threat area until the models can show
better agreement.

..Broyles.. 04/05/2026

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ACUS48 KWNS 060835
SWOD48
SPC AC 060834

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0334 AM CDT Mon Apr 06 2026

Valid 091200Z - 141200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
From Thursday to Saturday, mid-level flow over the south-central
U.S. is forecast to gradually transition from westerly to
southwesterly. In response, low-level moisture advection will likely
take place in the southern and central Plains. Isolated severe
storms will be possible near a front in the central Plains from late
Thursday afternoon into the early overnight period, as a low-level
jet strengthens. On Friday, weak instability is forecast to develop
over much of the southern Plains. Isolated to scattered
thunderstorms will be possible in the afternoon and evening across
parts of this airmass. An isolated severe threat may develop in some
areas, but deep-layer shear is forecast to be relatively weak over
much of the southern Plains, suggesting a more localized severe
potential.

On Saturday, the potential for severe storms is expected to increase
over parts of southern High Plains, as mid-level southwesterly flow strengthens. Model consensus suggests that the greatest severe
threat potential will be over parts of west Texas, where some models
have an axis of moderate instability in place by late Saturday
afternoon. Supercells with large hail and severe wind gusts will be
possible in the afternoon and evening, with storms that develop near
this instability axis.

...Sunday/Day 7 and Monday/Day 8...
On Sunday, an upper-level low and an associated trough is forecast
to move eastward across the Desert Southwest and northern Mexico.
Ahead of this trough, moderate instability is forecast to develop by
Sunday afternoon over much of the southern High Plains. Scattered
severe storms would be possible to the east of a west Texas dryline
in the afternoon and evening. A severe threat should continue into
the overnight as a low-level jet strengthens ahead of the
approaching trough.

On Monday, the upper-level trough is forecast to move quickly
northeastward across the central U.S, with an axis of moisture and
instability located in the Great Plains. Scattered severe storms
will be possible from Monday into Monday night from the southern
Plains northward into Upper Midwest. At this extended range, there
is still considerable uncertainty concerning the timing of the
trough. For this reason, will hold off on a threat area until the
models show better agreement.

..Broyles.. 04/06/2026

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ACUS48 KWNS 070858
SWOD48
SPC AC 070856

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Tue Apr 07 2026

Valid 101200Z - 151200Z

...DISCUSSION...
...Friday/Day 4 to Sunday/Day 6...
An upper-level trough will move eastward from the eastern Pacific on
Friday into the western U.S. on Saturday, as southwest mid-level
flow gradually strengthens over the south-central states. In
response, low-level moisture advection will continue over the Great
Plains. Ahead of the western U.S. trough, a subtle shortwave trough
is forecast to move into the southern High Plains Saturday
afternoon. A severe threat will be possible ahead of and near the
trough during the afternoon and evening.

On Sunday, the western U.S. upper-level trough is forecast to move
quickly east-northeastward into the southern Rockies. Ahead of the
trough, a moist and moderately unstable airmass is forecast over
much of the southern and central Plains by afternoon. Scattered
thunderstorms appear likely to develop over much of this airmass
during the afternoon and evening. Moderate to strong deep-layer
shear appear likely to be in place, which will be favorable for
severe storms. Supercells with large hail, severe wind gusts and a
tornado threat will be possible. An isolated severe threat may also
develop in parts of the north-central U.S.

...Monday/Day 7 and Tuesday/Day 8...
A secondary upper-level trough is forecast to move into the Desert
Southwest on Monday. Ahead of this system, a moist and unstable
airmass is forecast to remain in place from the southern Plains north-northeastward into the Upper Midwest. Although a severe threat
will be possible along much of the instability corridor, the
greatest threat is expected to develop in the southern Plains, where
model forecasts show the most favorable environment.

On Tuesday, model forecasts have some agreement concerning the
timing of the trough, which is forecast to eject northeastward
across the southern and central Plains. Ahead of the trough, there
is large variance among the models concerning the distribution of
instability. If a moderately unstable airmass is in place by Tuesday
afternoon ahead of the ejecting system, a severe threat will be
likely from the southern Plains into the mid to upper Mississippi
Valley. However, the system will probably be slower than forecast,
which adds considerable uncertainty this late in the period.

..Broyles.. 04/07/2026

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ACUS48 KWNS 080856
SWOD48
SPC AC 080854

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Wed Apr 08 2026

Valid 111200Z - 161200Z

...DISCUSSION...
...Saturday/Day 4 to Monday/Day 6...
On Saturday, mid-level southwesterly flow will strengthen over the
central U.S., as an upper-level system moves to near the West Coast.
A moist airmass will be in place over the southern and central
Plains, as a low-amplitude shortwave trough moves across the region. Large-scale ascent along with warming surface temperatures will
result in scattered thunderstorm development over much of west Texas
Saturday afternoon. MLCAPE is expected to peak near 1000 J/kg in
some areas, with 0-6 km shear being in the 30 to 40 knot range over
much of the southern High Plains. This should be sufficient for a
severe threat, with large hail and severe wind gusts possible.

From Saturday night into Sunday, strong moisture advection is
forecast over the Great Plains. By Sunday afternoon, moderate
instability is expected to be in place over much of this airmass.
Isolated to scattered severe thunderstorms are expected throughout
much of the moist sector during the afternoon and evening. Some
model forecasts move a 50 to 60 knot mid-level jet through central
and northeast Texas during the afternoon and evening. If this
happens, then a substantial severe threat would be possible from
parts of central and north Texas into Oklahoma. Severe storms,
including supercells with large hail, wind damage and a tornado
threat would be possible in areas that destabilize the most.

On Monday, a moist and unstable airmass is forecast to remain from
the southern Plains extending north-northeastward into the Upper
Midwest. Strong to severe thunderstorm development will be possible
over much of the instability corridor in the afternoon and evening.
The greatest potential for severe storms is forecast from the
southern Plains north-northeastward into the lower Missouri Valley
and upper Mississippi Valley, where the models develop moderate
instability and have 0-6 km shear mostly in the 30 to 40 knot range.
Severe storms with large hail, wind damage and a tornado threat will
be possible.

...Tuesday/Day 7 and Wednesday/Day 8...
The western U.S. trough is finally forecast to approach the southern
Plains on Tuesday, where a moist and unstable airmass should be in
place. Some solutions suggest that a mid-level jet will move into
the southern Plains Tuesday afternoon. This would create strong
deep-layer shear over parts of the moist sector, suggesting that a
substantial severe threat will be possible. Although there is still
spatial uncertainty regarding this scenario, current model forecasts
would support supercells with large hail, severe wind gusts and some
tornadoes.

On Wednesday, a shortwave trough is forecast to move through the
central states, with a southwest-to-northeast corridor of moderate
instability in place by afternoon from northeast Texas into western
Ozarks. This would be favorable for severe storms. However, at this
extended range, considerable uncertainty exists concerning severe
threat magnitude and spacing.

..Broyles.. 04/08/2026

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ACUS48 KWNS 090900
SWOD48
SPC AC 090858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Thu Apr 09 2026

Valid 121200Z - 171200Z

...DISCUSSION...
...Sunday/Day 4 to Tuesday/Day 6...
On Sunday, southwesterly mid-level flow will be in place across much
of the nation. At the surface, a moist airmass will be located from
the southern Plains north-northeastward into the Upper Midwest. Much
of this corridor is forecast to become moderately unstable by
afternoon. The greatest potential for severe storms will likely be
in the southern and central Plains, where some solutions have a
subtle shortwave trough. Moderate deep-layer shear and steep lapse
rates will be favorable for supercells with large hail and severe
wind gusts.

Mid-level flow is forecast to gradually strengthen across the
central U.S. on Monday. In response moisture advection will continue
in the Great Plains. By Monday afternoon, moderate instability
should be in place from north Texas northward into the upper
Mississippi Valley. Isolated to scattered thunderstorms are expected
to develop across this airmass Monday afternoon and evening.
Moderate deep-layer shear and steep lapse rates will again be
favorable for severe storms capable of large hail and severe wind
gusts. A tornado threat may also develop.

On Tuesday, an upper-level trough is forecast to move eastward into
the southern Rockies, as an associated mid-level jet streak ejects northeastward across the southern High Plains. A moderately unstable
airmass will likely be in place by afternoon from the southern
Plains northeastward into mid to upper Mississippi Valley and
southern Great Lakes. Strong deep-layer shear is forecast over the
southern and central Plains, where a substantial severe threat will
be possible. Supercells with large hail, wind damage and tornadoes
are expected Tuesday afternoon and evening. An upgrade will be
possible across parts of the threat area, once confidence increases
on the timing of the ejecting trough.

...Wednesday/Day 7 and Thursday/Day 8...
The upper-level trough is forecast to move eastward across the
central U.S. on Wednesday, as a cold front advances southeastward
through the Great Plains and Upper Midwest. Moderate instability is
forecast to develop ahead of much of the front. Thunderstorms that
form in areas that destabilize sufficiently could have a severe
threat. The severe potential will likely continue into Thursday, as
the front advances southeastward into the mid Mississippi Valley.
However, model spread concerning the position of the front and
timing of the trough increases substantially toward mid week,
suggesting a lot of uncertainty exists at this extended range in the
period.

..Broyles.. 04/09/2026

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ACUS48 KWNS 100830
SWOD48
SPC AC 100828

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0328 AM CDT Fri Apr 10 2026

Valid 131200Z - 181200Z

...DISCUSSION...
...Days 4-6/Mon-Wed -- Central/Southern Plains to the Midwest...

There is quite a bit of uncertainty regarding severe
potential/evolution during the Monday-Wednesday period. An upper
trough will slowly pivot across the West on Monday, and emerge over
the central/southern Rockies by early Wednesday before finally
ejecting across the Plains and toward the Mid/Upper MS Valley on
Wednesday. During this time, broad southwesterly deep-layer flow
will overspread the Plains into the Mid/Upper MS Valley.

On Monday, a surface low will develop over the northern/central
Plains, with a dryline extending southward across KS/OK/TX and a
warm front extending across southern MN/WI. Several lead shortwave
impulses will move across the Plains, though height tendencies will
remain mostly neutral. Nevertheless, cooling aloft will support
steep midlevel lapse rates and increasing boundary layer moisture
(surface dewpoints in the low/mid 60s F) will support moderate to
strong destabilization. During the evening, a southwesterly
low-level jet will increase across the Plains, overspreading the
surface dryline. Vertically veering wind profiles and 30-40 kt
effective shear magnitudes would support supercells capable of all
hazards, though storm coverage remains uncertain.

By Tuesday, the GFS becomes more progressive with the western
trough, ejecting it into the Plains by early Wednesday, whereas the
ECMWF hangs the trough back west and is slower. Nevertheless, a
similar airmass will be in place across the warm sector east of a
dryline across the Plains and to the south of a warm front draped
across the Great Lakes. Isolated convection may develop along the
dryline across the Plains, posing a supercell/all-hazards risk.
Higher storm coverage appears more likely across portions of the
Mid/Upper MS Valley/Great Lakes vicinity closer to a surface low.

On Wednesday, the upper trough should progress from the Plains to
the Great Lakes while weakening some. A surface cold front will
develop southeast across portions of the central U.S. and some
severe risk should persist along/ahead of this boundary. How
convection evolves on Tuesday into Wednesday will impact where the
greatest severe risk will develop, but at least some risk should
exist from portions of the southern Plains to the Mid-MS Valley.

...Days 7-8/Thu-Fri...

Predictability is low heading into the end of the forecast period on
Thursday and Friday as large spread exists among medium range
guidance. However, western U.S. upper troughing may persist,
suggesting some severe thunderstorm potential could persist for
parts of the Plains late in the work week.

..Leitman.. 04/10/2026

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ACUS48 KWNS 110846
SWOD48
SPC AC 110844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Sat Apr 11 2026

Valid 141200Z - 191200Z

...DISCUSSION...
...Day 4/Tue -- Southern Plains to Great Lakes...

A shortwave upper trough embedded within the larger-scale western
U.S. trough will eject across portions of the Plains to the Upper
Midwest on Day 4/Tue. As this occurs, a surface low will deep over
the central Plains and lift northeast across the Upper Midwest/Great
Lakes. Some uncertainty remains regarding the exact evolution of
this system, mainly due to differences in medium range guidance with
respect to surface low placement and timing of the upper shortwave
trough. Nevertheless, a moist and unstable airmass is expected ahead
of the low and to the east of a Plains dryline and south of a Great
Lakes warm front. Thunderstorm development should be more widespread
along these boundaries compared to prior days given stronger
large-scale ascent will overspread the central U.S., and height
falls will result in a more robust low-level jet response. As a
result, an all-hazards severe event is expected from the southern
Plains into portions of the Upper Midwest/Great Lakes vicinity on Tuesday/Tuesday night.

...Day 5/Wed -- Southern Plains to the Midwest...

Medium range guidance varies heading into Wednesday with the
operational GFS much more progressive and lower amplitude than the
operational ECMWF. The AIGFS is much more in-line with the
ECMWF/AIFS, so this period is weighted more toward those solutions.
It appears the upper trough over the southern Rockies will eject
across the Plains to the Mid-MS Valley during this time. A moist and
unstable airmass will reside across the region ahead of dryline
across western OK into central TX and a sagging cold front across
the Lower MO/Mid-MS Valley. Areas of precipitation could be ongoing
at the beginning of the period and does result in some uncertainty
regarding where stronger destabilization will occur. Nevertheless,
an overall favorable thermodynamic/kinematic parameter space will
overlap this corridor and isolated to scattered severe storms appear
likely.

...Days 6-8/Thu-Sat...

Medium range guidance depicts another trough developing across the
West on Day 6/Thu and quickly progressing east through the end of
the period. This could support a continued severe risk across parts
of the southern Plains into the Midwest in the Thursday or Friday
time frame. However, run to run consistency toward the end of the
forecast period has not been very good. Additionally, multiple
rounds of storms across the same areas earlier in the period may
impact later severe potential. Trends will be monitored and
probabilities may be needed in later outlooks.

..Leitman.. 04/11/2026

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ACUS48 KWNS 120841
SWOD48
SPC AC 120839

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0339 AM CDT Sun Apr 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...
...Day 4/Wed - Southern Plains to southern Wisconsin...

An upper trough will be oriented over the central/southern High
Plains Wednesday morning. This feature will shift east to the
Mississippi River by Thursday morning. As this occurs, strong
deep-layer southwesterly flow will overspread a moist and unstable
airmass from TX toward the Great Lakes. Some convection may be
ongoing Wednesday morning, resulting in some uncertainty regarding
airmass recovery and convective evolution during the
afternoon/evening. However, persistent southerly low-level flow
ahead of a dryline and continued warm advection should support areas
of airmass recovery. A mix of supercells and linear segments will be
possible, posing an all-hazards severe risk.

...Day 5/Thu...

Severe potential should be lower on Thursday as the upper trough and
weakens at it shifts east across the Ohio Valley. Widespread showers
and thunderstorms will be possible from parts of the Great
Lakes/Ohio Valley into the TN Valley, with modest instability and
limited heating tempering severe potential.

...Day 6/Fri - Southern Plains to Upper Midwest...

Medium range guidance has been fairly consistent the past several
forecast cycles in bringing a large-scale upper eastward from the
Rockies into the Plains Friday/Friday night. This should result in
surface cyclogenesis across portions of the Upper Midwest with a
trailing cold front extending into the southern Plains. Ahead of the
front, a seasonally moist/unstable airmass will be in place beneath strengthening southwesterly deep-layer flow. This should support a
severe risk ahead of the front.

...Days 7-8/Sat-Sun...

The upper trough will continue east over the eastern U.S. on
Saturday and Sunday. Stronger ascent will shift northeast into
Canada. Deep-layer flow parallel to the surface front and a
narrowing warm sector should limit severe potential.

..Leitman.. 04/12/2026

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ACUS48 KWNS 130846
SWOD48
SPC AC 130844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Mon Apr 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...
...Day 4/Thu - Mid-South vicinity...

An upper shortwave trough will develop northeast from eastern OK/TX
to the central/southern Appalachians on Thursday. Convection is
likely to be ongoing from the Mid-MS/Lower OH Valley to the ArkLaTex
region Thursday morning. This will likely temper downstream
destabilization (and overall severe risk), but a few strong storms
are possible across the Mid-South vicinity.

...Day 5/Fri - Southern Plains to Iowa...

Medium range guidance has been consistently showing an upper trough
over the western U.S. developing eastward toward the High Plains
Friday/Friday night. As this occurs, increasing deep-layer
southwesterly flow will overspread a seasonally moist and unstable
airmass. A lee low will deepen over the central/southern High
Plains, with a dryline extending across western OK/TX during the
afternoon. By evening and into the overnight hours, a cold front
will spread southeast across the central/southern Plains and Lower
MO Valley. This pattern will support a risk of severe storms across
the warm sector from OK to IA.

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

Some severe risk may persist into Saturday as a surface low deepens
over the Great Lakes and the cold front from the Day 5/Friday period
continues to sweep east across the Midwest to the Lower MS Valley,
becoming oriented across the Appalachians by Sunday morning. Severe
potential may depend on how convection on Friday evolves and impacts
the downstream airmass heading into Saturday morning, resulting in
low predictability at this time. Strong surface high pressure will
build across the Plains in the wake of the cold front, and Gulf
moisture will become cut-off as the front pushes well south into the
Gulf Basin. This should bring a reprieve from severe thunderstorm
potential Sunday into Monday as surface high pressure envelops much
of the CONUS east of the Rockies by the end of the period.

..Leitman.. 04/13/2026

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ACUS48 KWNS 140833
SWOD48
SPC AC 140831

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CDT Tue Apr 14 2026

Valid 171200Z - 221200Z

...DISCUSSION...
...Day 4/Friday - Southern Plains to Upper Midwest...

A strong upper trough oriented from Montana to the Southwest will
eject eastward to the Plains on Friday/Friday night. Southwesterly
mid/upper flow will intensify ahead of this feature, with 40-60 kt
850-700 mb flow forecast by late afternoon into the nighttime hours.
A somewhat complex surface pattern is forecast, with a lee low
deepening over the central/southern High Plains to western OK, and a
second surface low near the Mid-Missouri Valley developing northeast
into Ontario. A surface dryline will extend from the High Plains low
to near the western OK/TX panhandle border into central TX by
midday. Meanwhile, a cold front will be oriented from eastern MN
into central KS at midday.

Ahead of these surface features, a broad warm sector characterized
by mid/upper 60s F dewpoints will be in place as temperatures warm
into the 80s F. A plume of steep midlevel lapse rates will
overspread the region, resulting in moderate to strong
destabilization. Forecast soundings indicated impressive wind
profiles supporting supercells. Initial supercell storms capable of
all hazards (including very large hail and strong tornadoes) are
expected. During the evening, convection may grow upscale into a
squall line as storms near the Mississippi River, with an
accompanying increase in damaging wind potential.

...Day 5/Saturday - Ohio Valley/Great Lakes vicinity...

A severe risk will likely continue into Saturday as the upper trough
continues to strengthen and shift east from the Plains to the Great Lakes/Midwest. Strong deep-layer flow parallel to an
eastward-advancing cold front will overspread a moist and at least
weakly unstable downstream airmass through evening. This will favor
a line of convection with damaging wind potential.

...Days 6-8/Sunday-Tuesday...

The surface cold front will continue east on Sunday, moving offshore
the Atlantic and Gulf coasts during the afternoon. Severe potential
appears limited by weak instability and mainly anafrontal
precipitation across the Southeast to Eastern U.S. on Sunday.
Surface high pressure and a dearth of boundary layer moisture in the
wake of the cold front will preclude thunderstorm activity on
Monday. By the end of the period, medium range guidance depicts
another upper trough moving into the western U.S. and Gulf return
flow will advect moisture back into the southern Plains. However,
severe thunderstorm potential appears low at this time.

..Leitman.. 04/14/2026

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ACUS48 KWNS 140848
SWOD48
SPC AC 140846

Day 4-8 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0346 AM CDT Tue Apr 14 2026

Valid 171200Z - 221200Z

CORRECTED FOR DAY 5 GRAPHIC LABEL

...DISCUSSION...
...Day 4/Friday - Southern Plains to Upper Midwest...

A strong upper trough oriented from Montana to the Southwest will
eject eastward to the Plains on Friday/Friday night. Southwesterly
mid/upper flow will intensify ahead of this feature, with 40-60 kt
850-700 mb flow forecast by late afternoon into the nighttime hours.
A somewhat complex surface pattern is forecast, with a lee low
deepening over the central/southern High Plains to western OK, and a
second surface low near the Mid-Missouri Valley developing northeast
into Ontario. A surface dryline will extend from the High Plains low
to near the western OK/TX panhandle border into central TX by
midday. Meanwhile, a cold front will be oriented from eastern MN
into central KS at midday.

Ahead of these surface features, a broad warm sector characterized
by mid/upper 60s F dewpoints will be in place as temperatures warm
into the 80s F. A plume of steep midlevel lapse rates will
overspread the region, resulting in moderate to strong
destabilization. Forecast soundings indicated impressive wind
profiles supporting supercells. Initial supercell storms capable of
all hazards (including very large hail and strong tornadoes) are
expected. During the evening, convection may grow upscale into a
squall line as storms near the Mississippi River, with an
accompanying increase in damaging wind potential.

...Day 5/Saturday - Ohio Valley/Great Lakes vicinity...

A severe risk will likely continue into Saturday as the upper trough
continues to strengthen and shift east from the Plains to the Great Lakes/Midwest. Strong deep-layer flow parallel to an
eastward-advancing cold front will overspread a moist and at least
weakly unstable downstream airmass through evening. This will favor
a line of convection with damaging wind potential.

...Days 6-8/Sunday-Tuesday...

The surface cold front will continue east on Sunday, moving offshore
the Atlantic and Gulf coasts during the afternoon. Severe potential
appears limited by weak instability and mainly anafrontal
precipitation across the Southeast to Eastern U.S. on Sunday.
Surface high pressure and a dearth of boundary layer moisture in the
wake of the cold front will preclude thunderstorm activity on
Monday. By the end of the period, medium range guidance depicts
another upper trough moving into the western U.S. and Gulf return
flow will advect moisture back into the southern Plains. However,
severe thunderstorm potential appears low at this time.

..Leitman.. 04/14/2026

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ACUS48 KWNS 150755
SWOD48
SPC AC 150753

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 AM CDT Wed Apr 15 2026

Valid 181200Z - 231200Z

...DISCUSSION...
...Day 4/Sat - Ohio Valley...

An upper trough will overspread the Great Lakes and Midwest on
Saturday. At the surface, a cold front will sweep east across the
region during the day. Destabilization will likely be limited by
downstream cloud cover within a strong low-level warm advection
regime ahead of the front. Additionally, convection will likely be
ongoing in the vicinity of the front from Lower MI into IN/IL.
Nevertheless, strong mid/upper flow (40-60 kt in the 850-700 mb
layer) will support strong to severe convection even amid weak
instability. As such, a damaging wind gust risk will accompany
linear convection moving across the region during the day into
evening.

...Days 5-6/Sun-Mon...

Strong high pressure in the wake of the cold front from the Day 4
period will overspread much of the CONUS east of the Rockies early
next week. A dry/stable airmass will preclude thunderstorm
potential.

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

An upper trough is forecast to develop across the western U.S. Tuesday/Wednesday. This will result in lee trough development across
the High Plains, and strengthening south/southeasterly low-level
flow will transport Gulf moisture northward across the southern
Plains. Medium range guidance varies on whether or not this western
trough will eject into the Plains during this time, or if upper
ridging will be maintained. If the trough ejects, severe potential
could develop across portions of the southern/central Plains
Tuesday/Wednesday, though predictability is too low at this time to
introduce severe probabilities.

..Leitman.. 04/15/2026

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ACUS48 KWNS 160840
SWOD48
SPC AC 160838

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Thu Apr 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
Severe thunderstorm potential will be low through at least Day
6/Tuesday. In the wake of a cold front moving offshore the Atlantic
coast and into the Gulf, strong surface high pressure will build
east of the Rockies and persist across parts of the South and East
through Day 6/Tuesday. As a result, a dry and stable boundary layer
will preclude severe thunderstorm potential.

By the middle of the week, and upper trough is forecast to
overspread the western U.S. As this occurs, lee surface troughing
will allow for increasing southerly winds over the Plains, and Gulf
moisture will begin to return northward Days 7-8/Wed-Thu. It remains
uncertain if the upper trough will begin to eject eastward toward
the Plains at the end of the period. If this occurs, some severe
potential may develop across the Plains, though predictability is
low.

..Leitman.. 04/16/2026

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ACUS48 KWNS 170743
SWOD48
SPC AC 170741

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0241 AM CDT Fri Apr 17 2026

Valid 201200Z - 251200Z

...DISCUSSION...
A dry, continental airmass will persist across most of the CONUS for
the first part of next week. Severe weather chances will start to
increase by the middle of the week and into the later part of the
week. Forecast guidance consistently shows mid 60s F dewpoints
across the Plains and into the Midwest. However, aloft the pattern
remains quite uncertain. The ECMWF and the GEFS and EPS all show a
developing large-scale trough centered across the western CONUS with
multiple shortwave troughs which could result in severe weather
Day6/Wed to Day 8/Fri. However, the 00Z GFS and the EC-AIFS show a
consolidated mid-level trough which could result in a much more
substantial severe weather event across the central/southern Plains.
At this time, uncertainty is too high for specific risk areas, but
Day6/Wed to Day 8/Fri will likely feature multiple days of severe
weather across portions of the central/southern Plains.

..Bentley.. 04/17/2026

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ACUS48 KWNS 180742
SWOD48
SPC AC 180740

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0240 AM CDT Sat Apr 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
Initially dry conditions will keep the severe weather threat low on
D4/Tuesday. As a mid-level trough traverses the Rockies on Monday,
lee troughing will strengthen on D5/Wednesday. This will bring
substantial moisture return across the Plains. Given the early stage
moisture return, more than an isolated severe weather threat appears
unlikely on D5.

A more substantial severe weather threat is anticipated on Day
6/Thursday. The evolution of the mid-level trough still remains
unclear, but an overall pattern featuring broad troughing across the southern/central Plains, moderate to strong instability, and a sharp
dryline, could support at least isolated supercells Thursday
afternoon/evening. Have added a 15% area from western/central
Oklahoma into southern/eastern Kansas where the severe weather
threat seems likely regardless of how exactly the mid-level pattern
evolves.

The uncertainties discussed for Day 6 become greater on Day 7 and
beyond. Persistent troughing across the Plains and considerable
instability suggest that severe weather is likely on Friday (and
likely into the weekend). However, the progression of the mid-level
trough and the associated surface features need to become more clear
before a 15% area can be defined for these days.

..Bentley.. 04/18/2026

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ACUS48 KWNS 190902
SWOD48
SPC AC 190900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Sun Apr 19 2026

Valid 221200Z - 271200Z

...DISCUSSION...
A western trough will take hold in the days preceding this
convective period. Ahead of this trough moisture will return
northward through the central Plains, with 50F dewpoints reaching
perhaps as far north as the Canadian border during Wednesday/Day-4.
This return flow setup and western trough will set the stage for
multiple days of severe weather potential.

On Wednesday/Day-4, a lobe of vorticity will eject northeast out of
the western longwave trough across the central and northern Plains.
As this occurs, surface cyclogenesis should take place across the
far northern Plains. To the south of this surface low, a dryline
should sharpen across western Nebraska and Kansas. At the same time,
vertical shear should strengthen as the shortwave moves northeast
across the region. The kinematic profiles will support supercells
initiating along the dryline. However, concerns remain about the
quality of the moisture to the east of the dryline and subsequently
as to the number of potential thunderstorms that may develop. This
uncertainty precluded the introduction of unconditional 15%
probabilities at this time.

On Thursday/Day-5, the shortwave trough/midlevel low will deepen as
it slowly moves north-northeast during the day. This will help
maintain a strong surface cyclone across the northern Plains, with
strong southerly winds advecting Gulf moisture northward to the east
of the north-south oriented frontal boundary. Showers and
thunderstorms will be possible along and east of the aforementioned
frontal boundary across a large portion of the central US. Strong
vertical wind shear across this frontal boundary will promote severe
potential from Oklahoma northward to perhaps as far north as
Minnesota. The northern extent of the severe potential will be
delimited by the degree of moisture return, and have expanded the
unconditional 15% probability area northward into Iowa to account
for the increasing confidence in severe thunderstorm potential.

Overnight Thursday/Day-5, a surface cold front, augmented by
convective outflow, should push east across the northern and central
Plains and south-southeast across the southern Plains. Another round
of severe thunderstorms will be possible on Friday/Day-6 across
portions of northeast Texas/northern Louisiana and much of Arkansas
as diurnal heating of a moist airmass results in MUCAPE values
between 1000-2000 J/kg beneath modest vertical shear associated
persistent southwest midlevel flow.

The severe potential will likely persist into Saturday/Day-7 and
Sunday/Day-8 across portions of the southern Plains and northern
Gulf Coast states. Here, persistent western troughing will maintain
an increasingly moist airmass along and south of the aforementioned
frontal boundary. The location of this frontal boundary will likely
be significantly impacted by the repeated rounds of thunderstorms in
the prior days. Model guidance is in general agreement that at least
modest westerly/southwesterly flow will persist across the southern
Plains, with episodic perturbations traversing this flow field
downstream of the broader large-scale western trough. However,
significant differences remain with respect to the timing, strength,
and location of any of these perturbations to attempt to highlight unconditional severe probabilities.

..Marsh.. 04/19/2026

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ACUS48 KWNS 200900
SWOD48
SPC AC 200858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Mon Apr 20 2026

Valid 231200Z - 281200Z

...DISCUSSION...
In the days preceding this forecast period, a long-wave trough will
develop across the western US. This feature will persist across the
western and central US through the forecast period supporting a
multi-day severe weather threat across portions of the central US.

On Thursday/Day-4, a lobe of vorticity will rotate around the closed
midlevel low across the northern Rockies. This will reinforce a
surface cyclone as it moves north into Canada. As this low moves
north, a combined dryline/cold front will move east into an
increasingly moist environment across the central Plains. The
airmass ahead of the front should destabilize during the day
Thursday, with MUCAPE values over 1000 J/kg possible into portions
of Minnesota.

Thunderstorms should develop across portions of northeast Kansas
into Iowa during the late afternoon as height falls overspread the
surface front. These storms should quickly build southward along the
front into portions of Oklahoma and southern Kansas. Kinematic
fields initially should support supercells, but midlevel flow will
increasingly become parallel to the front suggesting that storms
will grow upscale into one or more linear segments.

The surface front, augmented by convective outflows, will continue
to push south and east into the Southern Plains and the greater
ArkLaTex region overnight Thursday into Friday/Day-5 before stalling
out. Forecast soundings along and ahead of the frontal boundary
indicate an unstable, uncapped environment with vertical shear
between 30-40 knots should support additional severe thunderstorms
Friday afternoon into the evening/overnight across portions of
eastern Oklahoma and Arkansas.

By Saturday/Day-6, the larger-scale flow across the southern Plains
will begin to respond to a low-latitude trough moving into southern
California by once again becoming increasingly southwesterly.
Embedded perturbations within this southwest flow ahead of the main
trough will support an ongoing severe threat across the southern
Plains. However, the location of various surface boundaries
(dryline, outflow, frontal) will be predicated on the evolution of
prior days of convection and the timing of the aforementioned
perturbations in the midlevel flow. Thus, while pattern recognition
suggests severe weather will be possible on Days 6,7, and 8,
certainty as to the location of greatest severe potential on any
given day remains too low to highlight with unconditional
probabilities at this time.

..Marsh.. 04/20/2026

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ACUS48 KWNS 210901
SWOD48
SPC AC 210859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Tue Apr 21 2026

Valid 241200Z - 291200Z

...DISCUSSION...
... An active severe weather pattern is expected through much of the
forecast period ...

Broadly cyclonic midlevel flow will persist through much of the
forecast period to the south of a closed upper low over
south-central Canada. This will place much of the Southern Plains in
westerly or southwesterly mid- and upper-level flow each day. At the
same time low-level pattern will support southerly flow from the
surface up through 850 mb across the same region. The result will be
an increasingly moist airmass to the east of a north-south dryline
across western Oklahoma and Kansas, and to the south of a remnant
west-to-east frontal boundary.

Diurnal heating of this moist airmass will result in afternoon
MUCAPE values around 2000-3000 J/kg Friday and Saturday beneath
30-40 knots of vertical shear. Model guidance continues to show
several perturbations within the midlevel flow traversing the
Southern Plains on Friday into Sunday morning. The result will be
multiple rounds of severe thunderstorms. The exact location and
dimensions of these daily severe threats will likely be augmented by
the prior days' convection, but the overall pattern supports near
daily severe potential across much of the Southern Plains.

On Sunday (Day 6) a stronger, yet compact, midlevel wave is forecast
to move northeast across Oklahoma. This wave is forecast to induce
cyclogenesis across western Oklahoma, which should act to sharpen a
dryline. To the east of the dryline, strong southerly winds will
support surface dewpoints increasing into the upper 60Fs to perhaps
low 70Fs. Diurnal heating of this airmass will result in MUCAPE
values nearing 4000 J/kg across central Oklahoma. Deep-layer shear
approaching 50 knots will overspread the region during the afternoon
as the main wave approaches. Although global models are struggling
to initiate convection along the dryline, pattern recognition would
support a significant severe weather threat Sunday evening. The lack
of model convective initiation results in enough uncertainty to
preclude the introduction of 30% unconditional severe probabilities.
All severe hazards will be possible on Sunday.

The severe threat will continue into Monday/Day-7 as the midlevel
low and surface cyclone translate east into the lower Mississippi
Valley. The severe threat may continue into Tuesday/Day-8 across
portions of the Southeast US, although numerous days of preceding
convection should use up the steep lapse rate reservoir to the west
resulting in too much uncertainty to introduce unconditional severe probabilities at this time.

..Marsh.. 04/21/2026

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ACUS48 KWNS 220902
SWOD48
SPC AC 220900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Wed Apr 22 2026

Valid 251200Z - 301200Z

...DISCUSSION...
An active severe weather pattern will continue through early next
week.

On Saturday/Day-4, model guidance continues to show thunderstorms
developing during the late afternoon and early evening hours along a
lifting warm front across the Southern Plains. Along and south of
this boundary, the environment will be strongly unstable with MUCAPE
values between 2000-3000 J/kg as a low-level jet continually advects
mid 60Fs dewpoints north across the boundary. Effective layer shear
around 40 knots would support an initial supercell threat that
should grow upscale into bowing segments overnight. A 30% area is
introduced across southwest Kansas into east-central Oklahoma for
the expectation is for strong bowing segments to move east-southeast
overnight into a strong low-level jet. These storms will be capable
of producing strong winds, large hail, and QLCS tornadoes.

On Sunday/Day-5, ongoing convection across southeast Kansas and
western Missouri at the start of the period may pose a continued
risk of hail and damaging winds, and this convection may persist
into mid morning. To the west, continued moist low-level advection
will allow for surface dewpoints to rise into the upper 60Fs to low
70Fs across central Oklahoma to the east of a sharp dryline. At the
same time, a low-amplitude shortwave should approach the Southern
Plains during the late afternoon and evening hours, with a
mid-990-millibar surface low developing across northwest Oklahoma
along the dryline. The result of this setup will be a volatile
atmosphere where MLCAPE values around 4000 J/kg exist within a
strongly shear environment (vertical shear nearly 50 knots). Should thunderstorms initiate, a high-end severe weather threat could
materialize during the late afternoon and evening hours across
central and eastern Oklahoma and southern Kansas. However, global
models continue to struggle to develop convection within this
environment despite model guidance having modest upward vertical
velocities overspreading the dryline. Pattern recognition suggests
the need for a 30% severe area for this potential despite the lack
of a QPF signal in the global models, and have opted to add one with
this forecast. The location of this 30% will likely need to be
refined in subsequent outlooks.

The severe threat should continue into Monday/Day-6 across portions
of the Lower Mississippi Valley. Strong storms should develop along
and ahead of an eastward moving cold front. MUCAPE of 2000-3000 J/kg
and 40-knots of deep-layer shear will support supercell
thunderstorms capable of all severe hazards. The location, number,
and intensity of these supercells will likely be modulated by the
events of Sunday. Specifically, if widespread convection does not
occur Sunday across the Southern Plains, a more robust reservoir of CAPE/lapse-rates will be available to thunderstorms across the Lower Mississippi Valley on Monday and a higher-end severe potential may
develop. This will be monitored in subsequent forecasts.

By Tuesday/Day-7 into Wednesday/Day-8, uncertainty in the severe
potential across the southeast increases too much to have confidence
in identifying specific locations. Although, as the mesoscale
details become cleared in the preceding days, areas may need to be
added in subsequent forecasts.

..Marsh.. 04/22/2026

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ACUS48 KWNS 230905
SWOD48
SPC AC 230904

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0404 AM CDT Thu Apr 23 2026

Valid 261200Z - 011200Z

...DISCUSSION...
A multi-day severe weather event remains on track for Sunday/Day-4
evening through Monday/Day-5, with additional severe storms possible
during the rest of the forecast period.

A vigorous, yet compact, negatively tilted midlevel wave is forecast
to move across the Southwest and eject into the Plains Sunday
evening into Monday. As this wave ejects into the central US, strong
surface cyclogenesis is expected over the Central Plains on Sunday
evening. The flow around this low will help draw very rich boundary
layer moisture northward to the east of a sharpening dryline. The
atmosphere on Sunday across the Southern and Central Plains should
remain capped for much of the day, allowing extreme instability
(SBCAPE/MUCAPE values in excess of 4000 J/kg) to develop. As modest
height falls overspread the dryline during the late afternoon and
evening hours, the expectation is that at least a few storms will be
able to break through the cap. While 20260423/00Z global guidance is
still struggling to produce widespread precipitation along and east
of the dryline, the control members are now at least producing light
QPF along the dryline which would tend to support the idea that
isolated convection will be possible.

The environment to the east of the dryline will be very unstable and increasingly sheared as enhanced midlevel flow overspreads the warm
sector. Additionally, as the surface low deepens during the evening
hours, low-level winds will respond by rapidly increasing to greater
than 50 knots. The result will be the potential for any thunderstorm
that develops and sustains itself to become strong supercells
capable of producing all severe hazards, including significant
severe.

As the main wave continues to lift northeast on Monday, the surface
low should rapidly move from the Central Plains into the Upper
Mississippi Valley. As this occurs, a surface warm front will
rapidly lift northward on the nose of an intense low-level jet. This
low-level jet will likely result in widespread precipitation to the
north of the front, which will have impacts on the northern extent
of Monday afternoon's severe potential.

By Monday afternoon, additional thunderstorms are expected to
develop along and east of an advancing dryline/cold front in an
increasingly unstable atmosphere. Diurnal heating of a boundary
layer with low-to-mid-60Fs dewpoints should result in SBCAPE/MUCAPE
values between 2000-3000 J/kg. Additionally, vertical shear will
remain more than sufficient for supercells. All severe hazards will
remain possible with this convection, with the greatest
concentration of severe storms likely across the Mid-Mississippi
Valley where a 30% area was introduced.

Monday evening into the overnight hours will see a continued
potential for severe storms as the surface front pushes east into
the western portions of the Ohio Valley. Additionally, severe storms
will likely continue across the southwest portion of the front,
which will slowly begin to stall in a southwest-to-northeast or
west-to-east configuration across Arkansas into Kentucky.

Additional severe storms will be possible Tuesday/Day-6 through
Thursday/Day-8 across the Southern and Central Plains into the
Lower-to-Middle Mississippi Valley as cyclonic midlevel flow
persists atop a moist boundary layer with a frontal boundary
somewhere across the area. However, given the uncertainties in how
the convective evolution of Sunday and Monday will impact the
location of relevant surface features and the general uncertainty
associated with identifying the timing of midlevel perturbations
embedded within the broader scale cyclonic midlevel flow,
unconditional 15% severe probabilities will be deferred to
subsequent outlooks.

..Marsh.. 04/23/2026

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ACUS48 KWNS 240903
SWOD48
SPC AC 240901

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Fri Apr 24 2026

Valid 271200Z - 021200Z

...DISCUSSION...
Latest medium-range model output suggests that a significant short
wave perturbation emerging from the Southwest will pivot northeast
of the middle/lower Missouri Valley, into the upper Great Lakes
region, Monday through Monday night. It appears that the warm
sector of an associated sub-1000 mb surface cyclone will become
characterized by at least moderately large CAPE, ahead of the
dryline/cold front overspreading much of the middle Mississippi
Valley during the afternoon into evening. In the presence of strong
deep-layer shear, organized severe thunderstorm activity appears
probable. It remains a bit unclear the extent to which sustained
supercell development will be maintained, as opposed to convection
quickly growing upscale into one or more clusters/lines, but there
appears at least some potential for a few strong tornadoes, in
addition to large hail and potentially widespread strong to severe
wind gusts.

In the wake of this activity, into the middle to latter portion of
next week, convective potential becomes more unclear as strong flow
trends westerly, and broadly confluent across and east of the
Rockies, between broad mid-level troughing overspreading the
northern tier and broad mid-level ridging across the southern tier.
Another, initially notable, short wave perturbation emerging from
the southern mid-latitude/subtropical eastern Pacific is still
forecast to progress into the Southwest. But latest model output
suggests that it may become sheared while continuing across and east
of the southern Rockies, with only modest to weak surface
cyclogenesis currently forecast along a remnant frontal zone across
the southern Great Plains through Southeast.

..Kerr.. 04/24/2026

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ACUS48 KWNS 250857
SWOD48
SPC AC 250855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Sat Apr 25 2026

Valid 281200Z - 031200Z

...DISCUSSION...
In the wake of a significant surface cyclone, which may be in the
process of migrating northeast of the upper Great Lakes region by
12Z Tuesday, it appears that a cold front will gradually advance
across the Atlantic Seaboard and into the Gulf coast vicinity before
stalling later this work week into next weekend. It appears that
this will occur coincident with the southwestward suppression of
subtropical ridging, initially centered over southern Mexico and
influential as far north as the Gulf coast at the outset of this
period.

Near the southern periphery of the westerlies/northern periphery of
the subtropical ridging, there appears a similar signal in both
ECENS and GEFS related medium-range guidance concerning potential
for organized severe thunderstorm development by late Tuesday
afternoon into Tuesday evening. An evolving pre-frontal corridor of
moderate to strong potential instability across the Ark-La-Tex
through Ark-La-Miss vicinity may provide a focus for an upscale
growing thunderstorm cluster, aided by forcing for ascent and shear
associated with a mid-level speed maximum progressing across the
region.

Through the remainder of the week, into early next weekend, the
lingering frontal zone across the Gulf coast region may provide a
focus for occasional continuing thunderstorm development,
particularly as an initially notable short wave perturbation,
emerging from the southern mid-/subtropical latitudes of the eastern
Pacific, progresses east of the southern Rockies. However, barring
more substantive frontal wave development than currently forecast,
potential for organized severe convection remains unclear.

..Kerr.. 04/25/2026

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ACUS48 KWNS 260850
SWOD48
SPC AC 260848

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Sun Apr 26 2026

Valid 291200Z - 041200Z

...DISCUSSION...
In general, the latest medium-range model output suggests that the
prevailing split flow will continue to evolve in a manner that
results in a broadly confluent regime developing across and east of
the Rockies by mid week through next weekend. Within the northern
branch, it appears that a mid-level low will develop and deepen
within broad troughing overspreading the Northeast, while an
initially prominent subtropical high, centered over southern Mexico,
becomes suppressed, as the first in a series of developing southern
stream lows is forced inland across the southern tier of the United
States. It appears that this will be preceded by broad cool surface
ridging overspreading much of the central and eastern U.S., as far
south as the Gulf Coast region by Thursday. While associated
forcing for ascent and destabilization might support increasing
thunderstorm development across parts of central and southern Texas
late this work week, mostly above/to the cool side of a stalling
frontal zone, into Florida and adjacent portions of the Southeast by
late next weekend, the risk for severe weather appears relatively
minor at this time.

..Kerr.. 04/26/2026

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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 Mon Apr 27 2026

Valid 301200Z - 051200Z

...DISCUSSION...
Medium-range guidance continues to indicate that the prevailing
split flow will evolve in a manner that maintains a broadly
confluent regime across and east of the Rockies through this period.
Within the northern branch, it appears that a fairly significant low
will form within broad troughing overspreading the Northeast by
early next weekend, perhaps trailed by another developing low across
parts of the Upper Midwest/Great Lakes by early next week. At the
same time, an initially prominent subtropical high centered over
southern Mexico is forecast to become suppressed, as a mid/upper low
emanating from the subtropical eastern Pacific is forced eastward
into and through the confluent regime across the southern tier of
the United States.

It still appears that the shearing subtropical impulse, and perhaps
a trailing perturbation, will be preceded by broad cool surface
ridging overspreading much of the central and eastern U.S., as far
south as the Gulf Coast region by Thursday. The frontal zone on the
leading edge of this air mass is generally forecast to progress into
the Gulf Basin and Florida Peninsula, where it is likely to linger
through early next week. While forcing for ascent and
destabilization might support increasing thunderstorm development
across parts of central and southern Texas late this work week
(mostly above/to the cool side of the stalling frontal zone) into
Florida and adjacent portions of the Southeast by late next weekend,
the risk for severe weather still appears relatively minor at this
time.

..Kerr.. 04/27/2026

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ACUS48 KWNS 280858
SWOD48
SPC AC 280856

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Tue Apr 28 2026

Valid 011200Z - 061200Z

...DISCUSSION...
Medium-range guidance indicates that the evolving split flow may
maintain a broadly confluent mid-level regime across and east of the
Rockies through this period. While a broad area of lower mid-level
heights remains centered across the Ontario/Quebec and Upper Midwest
through Northeast, it appears that a more prominent blocking
ridge/high may evolve upstream near the British Columbia/Pacific
Northwest coast by late this coming weekend into early next week. A
developing low to its southeast may slowly progress inland across
California into the Southwest, with downstream mid-level ridging
building across the Rockies.

There is considerable model spread concerning embedded short wave
developments, but it appears that potential for stronger convection
will remain generally low for the time of year and confined to parts
of the southern tier of the U.S., perhaps including parts of the San
Joaquin Valley, as well as along a lingering frontal zone near or
just south of the Gulf into southern Atlantic coastal plain. Due to
a combination of low predictability and low severe weather
potential, severe weather probabilities are being maintained at less
than 15 percent through this period.

..Kerr.. 04/28/2026

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ACUS48 KWNS 280925
SWOD48
SPC AC 280923

Day 4-8 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0423 AM CDT Tue Apr 28 2026

Valid 011200Z - 061200Z

...DISCUSSION...
Medium-range guidance indicates that the evolving split flow may
maintain a broadly confluent mid-level regime across and east of the
Rockies through this period. While a broad area of lower mid-level
heights remains centered across the Ontario/Quebec and Upper Midwest
through Northeast, it appears that a more prominent blocking
ridge/high may evolve upstream near the British Columbia/Pacific
Northwest coast by late this coming weekend into early next week. A
developing low to its southeast may slowly progress inland across
California into the Southwest, with downstream mid-level ridging
building across the Rockies.

There is considerable model spread concerning embedded short wave
developments, but it appears that potential for stronger convection
will remain generally low for the time of year and confined to parts
of the southern tier of the U.S., perhaps including parts of the San
Joaquin Valley, as well as along a lingering frontal zone near or
just south of the Gulf into southern Atlantic coastal plain. Due to
a combination of low predictability and low severe weather
potential, severe weather probabilities are being maintained at less
than 15 percent through this period.

..Kerr.. 04/28/2026

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ACUS48 KWNS 290900
SWOD48
SPC AC 290858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Wed Apr 29 2026

Valid 021200Z - 071200Z

...DISCUSSION...
Latest medium-range guidance, in particular the ECENS and GEFS,
generally maintains forecast trends of prior runs concerning the
evolution of the large-scale features within the prevailing split
flow through this weekend into early next week. It appears that at
least a transient blocking high may evolve within amplified ridging
offshore of the British Columbia and adjacent Pacific Northwest
coast. To its south-southeast a notable mid-level low is forecast
to evolve within initial troughing slowly digging toward the U.S.
Pacific coast, with the low bottoming out offshore of the central/
southern California coast by early next week.

Downstream, it appears that a broad area of lower mid-level heights
will be maintained, with lowest heights perhaps reforming
west-northwestward from southwestern Quebec toward southern Hudson Bay/northwestern Ontario, contributing to the maintenance of a
confluent regime across and east of the Rockies.

Shorter wavelength developments within this pattern remain more
uncertain, particularly by the early to middle portion of next week,
when it appears that the offshore low will begin to progress inland
across California and the southern Sierra Nevada. Depending on the
timing of the inland progressing mid-level cold core with respect to
diurnal heating, this could be accompanied by relatively minor
severe weather potential across parts of the San Joaquin Valley next
Monday or Tuesday.

Downstream, southerly moist return flow into at least the southern
through central Great Plains, associated with deepening lee surface
troughing, may contribute to destabilization beneath building
mid-level ridging across and east of the southern Rockies. This
might be accompanied by increasing potential for at least widely
scattered strong to severe thunderstorm development on Tuesday.

Guidance suggests potential for more widespread organized severe
thunderstorm development could increase by Wednesday, but much will
depend on short wave developments which become rather uncertain by
this time.

..Kerr.. 04/29/2026

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ACUS48 KWNS 300902
SWOD48
SPC AC 300900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Thu Apr 30 2026

Valid 031200Z - 081200Z

...DISCUSSION...
Late this coming weekend into early next week, it still appears that
at least a transient blocking high may continue to evolve offshore
of the British Columbia/Pacific Northwest coast. It remains a bit
uncertain how long this will persist before becoming suppressed, and
an evolving low to its southeast is forced inland across southern
California into the Southwest.

Latest medium range guidance continues to indicate that it is
possible that a short wave perturbation could emerge from the
remnant low/troughing, in advance of another significant short wave
impulse emerging from the higher latitudes before amplifying
southeastward to the lee of the Rockies, through the Atlantic
Seaboard by the end of the period. However, it now appears probable
that modest troughing, perhaps with a continuing cyclonic
circulation, will linger near and south of the Southwestern
international border.

In lower levels, southerly moist return flow may commence by early
next week across the southern into central Great Plains as surface
troughing deepens to the lee of the Rockies. This may begin to more substantively advect northeastward toward the Ohio Valley, in
advance of a southward advancing cold front associated with the
digging mid-level troughing. However, there is notable spread among
the model output concerning potential surface cyclogenesis, near
and northeast of the Rockies.

Widely scattered strong to severe thunderstorm development appears
possible from parts of the central and southern Great Plains into
the Mississippi Valley by Tuesday, if not Monday. However,
inhibition associated with warm elevated mixed-layer air
overspreading the southern Great Plains may become a limiting
factor, as low-level moisture becomes more supportive of strong destabilization.

There remains at least some signal in the model output for
potentially more widespread strong to severe thunderstorm
development across the lower/middle Mississippi Valley into Ohio
Valley by next Wednesday, perhaps into Thursday. However, with
uncertainties remaining sizable at this extended time frame, severe probabilities still appear less than 15 percent.

..Kerr.. 04/30/2026

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ACUS48 KWNS 010736
SWOD48
SPC AC 010734

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 AM CDT Fri May 01 2026

Valid 041200Z - 091200Z

...DISCUSSION...
...Days 4-6/Mon-Wed -- Southern Plains...Mid/Lower MS
Valley...Southeast...

An upper trough will develop southward across the northern Plains
and Upper Midwest on Monday. At the same time, another upper trough
will be oriented over southern CA and offshore over the Pacific. In
response to modest height falls and increasing westerly flow across
the Rockies, a lee low will develop over the central/southern High
Plains. Increasing southerly low-level flow will allow modified Gulf
moisture to return northward ahead of a dryline across the southern
Plains, and to the south of a cold front developing southward across
the central Plains and Upper MS Valley. Isolated strong to severe
thunderstorms will be possible within the narrow moist/warm sector
ahead of these surface boundaries, particularly the cold front
across parts of the MO/Mid-MS Valley, as capping may persist further
south across the Southern Plains. Given modest boundary moisture
with north and east extent across the Midwest, it is uncertain how
robust convection may be and where the most favorable area for
severe storms may develop, precluding 15 percent probabilities at
this time for Day 4/Mon.

By Day 5/Tue, the jet associated with the eastward advancing
Southwest U.S. trough will being to phase with the upper trough over
the north-central U.S. This will bring strengthening southwesterly
flow to portions of the southern Plains and Mid-South vicinity while southwesterly low-level flow continues to transport Gulf moisture north/northeast ahead of a southeastward-advancing surface cold
front. The warm sector will become increasingly narrow toward the
Lower Ohio Valley, and any strong to severe thunderstorm potential
would likely focus from parts of Texas into Arkansas/far western
TN/KY. However, model guidance varies with regard to placement and
extent of potential convection ongoing Tuesday morning, which will
have implications for severe potential through the rest of the day.
Differences in the location of the surface front also add
uncertainty, precluding a 15 percent delineation.

Some strong to severe thunderstorm potential could persist into Day
6/Wed across parts of the Lower MS Valley and southeastern U.S. This
remains uncertain and will be influenced by convective evolution in
the days prior.

...Days 7-8/Thu-Fri...

The surface cold front is expected to move offshore the East Coast
on Day 7/Thu. Thunderstorm potential will continue ahead of the
front across the Southeast to the Mid-Atlantic, but severe potential
is uncertain as destabilization may be limited by widespread
rainfall and cloud cover. On Day 8/Fri, most of the CONUS will be
stable/dry behind the cold frontal passage. However, guidance
suggests a shortwave upper trough will approach the southern
Rockies/northern Mexico and surface cyclogenesis will maintain a
moist airmass across TX. If this occurs, some severe potential could
develop across parts of TX.

..Leitman.. 05/01/2026

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ACUS48 KWNS 020756
SWOD48
SPC AC 020755

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 AM CDT Sat May 02 2026

Valid 051200Z - 101200Z

...DISCUSSION...
...Days 4-5/Tue-Wed -- Southeast OK/ArkLaTex to Lower MS/TN
Valleys...

Southwesterly deep-layer flow will increase from the southern
Rockies to the Mid-South on Day 4/Tuesday as a southern stream
shortwave trough over the Southwest merges with an upper trough over
the Plains/Upper Midwest. At the surface, low pressure will develop
over the southern Plains and slowly progress east in AR as a cold
front develops southeast across OK/AR and the Lower OH Valley. Ahead
of the front, rich Gulf moisture will return northward, and 60s to
near 70 F dewpoints are forecast by Tuesday afternoon/evening across
southeast OK and the ArkLaTex. Timing of thunderstorm development is
a bit uncertain as shortwave ridging may overspread the southern
Plains vicinity through afternoon. However, forcing for ascent
should increase with the approach of the surface front and as a
low-level jet increasing Tuesday evening. Moderate instability and
strong vertical shear should support severe thunderstorm activity
near the cold front from late afternoon into Tuesday night.

On Day 5/Wednesday, the Plains upper trough will migrate east,
extending from the Upper Great Lakes to the Lower MS Valley by early
Thursday. The surface cold front will extend from the OH Valley into north/central TX Wednesday morning and slowly progress southeast
through the period. Gulf moisture will return north and east across
the southern U.S. ahead of the front. While deep-layer flow will
largely be parallel to the surface front, moist and unstable airmass
ahead of the front should support some risk for severe
thunderstorms.

...Days 6-8/Thu-Sat...

A deepening surface low will develop northward across the
Mid-Atlantic and Northeast on Thursday as a surface cold front
continues to shift east across much of the eastern U.S. While a
moist airmass will be in place across parts of the Southeast to the Mid-Atlantic, it is uncertain how much destabilization will occur
due to possibly widespread thunderstorm activity and cloud cover
(particularly from the Mid-Atlantic northward). Large-scale ascent
will become increasingly displaced to the north across the
Southeast, and convection may tend to be anafrontal. Trends will be
monitored and severe probabilities could become necessary for parts
of the eastern U.S. on Thursday in later outlooks.

Severe potential will be limited on Friday as the prior cold frontal
passages clears out Gulf moisture and surface high pressure envelops
much of the eastern half of the U.S. Weak upper troughing could
overspread the Rockies and High Plains by the end of the period,
allowing for Gulf moisture return across the Plains and an increase
in thunderstorm potential.

..Leitman.. 05/02/2026

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ACUS48 KWNS 030752
SWOD48
SPC AC 030750

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 AM CDT Sun May 03 2026

Valid 061200Z - 111200Z

...DISCUSSION...
...Day 4/Wed -- East TX to the Lower MS and TN Valley vicinity...

Strong southwesterly deep-layer flow will overspread the region
ahead of an upper trough pivoting east across the Plains toward the
Mid-MS Valley. At the surface, a cold front will be oriented from
the OH Valley to southern AR and central TX. Ahead of the front,
rich Gulf moisture will be in place across southern and eastern TX
into the Lower MS Valley eastward toward AL. Moderate to strong
destabilization is expected across the warm sector ahead of the southward-sagging cold front. Supercell wind profiles are evident in
forecast soundings. However, given linear forcing along the front
and deep-layer flow largely parallel to the boundary, it is
uncertain if discrete storms will be possible. Nevertheless, severe
potential is still expected with clusters and linear segments given
the favorable thermodynamic environment and strong vertical shear.

...Day 5/Thu - South TX and parts of the Southeast...

Some severe potential could persist into Thursday across south TX as
the cold front continues to develop southward across a very moist
and unstable airmass. However, large-scale ascent may be limited as
forcing associated with the eastern U.S. upper trough focuses well
northeast of the region. Shortwave upper ridging also may overspread
region ahead of an upper low/trough over northwest Mexico.

Additional strong or severe storms will be possible across parts of
the Southeast toward the Carolinas and Mid-Atlantic as the cold
front shifts east across that region. However, widespread
showers/thunderstorms and cloud cover may limit destabilization, and
convection could become anafrontal by this time.

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

Spread beings to increase across model guidance by the weekend,
though mean upper troughing across the East seems likely to persist.
This typically would not be ideal for severe potential. However, an
upper shortwave trough is forecast to move across the southern
Rockies into the southern Plains. Forecast guidance varies widely
with the timing and evolution of these features however, and
predictability is low.

..Leitman.. 05/03/2026

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ACUS48 KWNS 040732
SWOD48
SPC AC 040730

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Mon May 04 2026

Valid 071200Z - 121200Z

...DISCUSSION...
Large-scale upper troughing is expected to envelop much of the
eastern half of the CONUS for most of the forecast period. On Day
4/Thu, a surface cold front is expected to extend from the southern Mid-Atlantic to the central Gulf coast and southern TX. The front
should largely move offshore the Gulf and Atlantic coasts and over
northern FL by early Day 5/Fri. A moist airmass will be in place
ahead of the front and some severe thunderstorm potential could
develop. However, 15 percent or greater coverage is uncertain given
deep-layer flow parallel to the boundary, cloud cover and areas of showers/thunderstorms early Thursday, and large-scale ascent lifting
northeast away from better low-level moisture.

Severe potential appears low Days 5-6/Fri-Sat. Boundary layer
moisture will be limited due to the prior cold frontal passage and
surface high pressure in its wake. Some guidance suggests a weak
shortwave trough will migrate across the southern Rockies and
southern Plains on Friday, resulting in lee troughing and some Gulf
moisture return across TX Friday night into Saturday. This could
bring an increasing chance for thunderstorms across portions for TX
and perhaps the Lower MS Valley on Saturday, though severe potential
is uncertain given large model spread. By early next week, another
period of moisture return ahead of a shortwave trough ejecting from
the Rockies into the Plains/Midwest could bring another bout of
severe potential ahead of a cold front from the southern Plains to
the Southeast. However, timing and intensity of these features
varies across control, AI, and ensemble guidance, resulting in low predictability.

..Leitman.. 05/04/2026

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ACUS48 KWNS 050734
SWOD48
SPC AC 050732

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0232 AM CDT Tue May 05 2026

Valid 081200Z - 131200Z

...DISCUSSION...
Mean upper troughing will persist east of the Rockies for the Day
4-8 period. This will largely suppress northward transport of Gulf
moisture, except periodically across the southern Plains and
Southeast/Gulf coast states. Severe potential is expected to be low
on Day 4/Fri as surface high pressure dominates in the wake of a
prior cold frontal passage offshore the Gulf and Atlantic coasts. On
Day 5/Sat, lee troughing will allow for increasing
south/southeasterly low-level flow across the southern Plains and
Lower MS Valley, aiding in moisture return across these areas. This
could result in thunderstorm potential across the south-central
U.S., but severe potential is limited given a lack of stronger
forcing for ascent. By Days 6-7/Sun-Mon, another cold front is
forecast to move east/southeast across much of the U.S. east of the
Rockies. As the front impinges on a moist airmass across the
southern Plains to the Southeast and Mid-Atlantic, some severe
potential could develop. However, mid to upper-level flow is not
forecast to be overly strong and medium range guidance varies quite
a bit with respect to moisture and cold front timing, resulting in
low predictability.

..Leitman.. 05/05/2026

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ACUS48 KWNS 060744
SWOD48
SPC AC 060742

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 AM CDT Wed May 06 2026

Valid 091200Z - 141200Z

...DISCUSSION...
An upper shortwave trough will be located over TX on Day 4/Saturday.
Meanwhile, another upper shortwave trough will migrate from the
central Rockies into the into the central Plains on Saturday. These
features will result in modestly increasing mid/upper level
northwesterly flow across the Plains. At the surface, modest
southerly low-level flow will continue to transport Gulf moisture
northward across the southern Plains and Lower MS Valley. Weak
surface cyclogenesis is possible across the central/southern Plains
and a dryline will extend across western KS/OK/TX. This could be a
focus for thunderstorm development on Saturday. However, how far
north quality moisture return will occur (especially before Saturday night/early Sunday) is uncertain. Additionally, deep-layer flow is
not forecast to be very strong. While some strong to severe
thunderstorms could develop, confidence is too low to include severe probabilities.

By Day 5/Sunday, a large scale upper trough over the Plains will
shift east, extending from the lower Great Lakes to the eastern Gulf
by Monday morning. A surface low will move from the Midwest to the
eastern U.S. while a trailing cold front develops southeast across
the southern Plains and the Mid/Lower MS and OH Valleys. Ahead of
the front, a moist airmass will be in place across the south-central
to Southeast U.S. However, it is uncertain how much destabilization
will occur as widespread precipitation and cloud cover are possible.
Some strong to severe thunderstorm potential could develop, but
predictability is low at this time.

Heading into Days 6-8/Mon-Wed, mean troughing is likely to continue
across the East with broad northwesterly flow across the Plains. The
cold frontal passage on Sunday will likely suppress Gulf moisture on
Monday. Another cold front is forecast to move across portions of
the Plains and Midwest on Tuesday and any severe potential will
depend on timing and quality of moisture return into the central
U.S., which is uncertain. Overall, predictability is low late in the
forecast period.

..Leitman.. 05/06/2026

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ACUS48 KWNS 070730
SWOD48
SPC AC 070728

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0228 AM CDT Thu May 07 2026

Valid 101200Z - 151200Z

...DISCUSSION...
A progressive upper-level pattern is forecast during the Day
4-8/Sun-Thu period. Early in the period, an upper trough will move
from the Plains to the eastern U.S. through Day 5/Mon. Stronger
northwesterly flow will overspread the Plains during this time,
while a cold front will sag southward across TX and Gulf Coast
states. This will suppress boundary layer moisture across much of
the CONUS, but could bring some potential for strong thunderstorms
to parts of TX and the Southeast, though severe thunderstorm
potential appears marginal.

By Day 6/Tue, a deepening surface low is forecast across the central
Plains as a weak shortwave impulse migrating through northwesterly
flow aloft glaces the region. Increasing southerly low-level flow
will begin to transport Gulf moisture northward across portions of
the central U.S. through Day 7/Wed, and some increase in
thunderstorm potential is expected. At the same time an upper ridge
will begin to emerge over the Plains, which could lead to capping. Additionally, quality of moisture return is uncertain with northward
extent. Overall, severe potential appears marginal throughout the
Day 4-8/Sun-Thu period.

..Leitman.. 05/07/2026

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ACUS48 KWNS 080833
SWOD48
SPC AC 080831

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CDT Fri May 08 2026

Valid 111200Z - 161200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
Mid-level northwesterly flow is forecast to persist across much of
the central and eastern U.S. during the period from Monday to
Wednesday. A cold front is forecast to move through the Southeast on
Monday and into the Gulf and Florida on Tuesday and Wednesday.
Isolated severe thunderstorm development will be possible near and
ahead of the front each day, with the greatest potential for severe
Monday afternoon and evening in parts of southern Alabama, southern
Georgia, northern Florida and the coastal Carolinas. Isolated severe
wind gusts is expected to be the primary threat.

Further to the north on Tuesday, another cold front is forecast to
move southward through the central Plains and mid Mississippi
Valley. Although low-level moisture is forecast to remain somewhat
limited, enough instability could develop for an isolated severe
threat. The greatest potential would be in eastern Missouri and
southern Illinois in conjunction with a mid-level jet moving
southeastward through the region. Hail and isolated severe gusts
will be possible. A marginal severe threat could again develop near
the associated trough over the central Appalachians Wednesday
afternoon.

...Thursday/Day 7 and Friday/Day 8...
A shortwave ridge is forecast to move eastward toward the
Mississippi Valley on Thursday, as another shortwave ridge moves
into the High Plains on Friday. In the wake of each ridge, model
forecasts develop a north-to-south axis of instability in the Great
Plains. Isolated severe storms will be possible within this unstable
airmass on both Thursday and Friday. At this time, uncertainty is
substantial late in the day 4 to 8 period.

..Broyles.. 05/08/2026

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ACUS48 KWNS 090844
SWOD48
SPC AC 090843

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0343 AM CDT Sat May 09 2026

Valid 121200Z - 171200Z

...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5....
On Tuesday and Wednesday, northwesterly mid-level flow will be in
place over the central U.S. A shortwave trough is forecast to move southeastward into the upper Mississippi Valley on Tuesday, and into
the central Appalachians on Wednesday. Isolated severe thunderstorms
will be possible ahead of the trough each day, but weak instability
should keep any severe threat marginal.

...Thursday/Day 6 to Saturday/Day 8...
On Thursday, a shortwave ridge is forecast to move eastward across
the central U.S. A north-to-south axis of instability is forecast to
develop in the wake of the ridge across the Great Plains. Isolated
severe storms will be possible along parts of this corridor Thursday
afternoon and evening.

On Friday, a subtle shortwave trough is forecast to move eastward
across the central U.S. Moderate deep-layer shear is forecast to be
in place over a moist and unstable airmass from eastern Kansas
southward into Oklahoma, where isolated severe storms may develop
during the afternoon and evening.

On Saturday, strong low-level moisture advection is forecast to
develop over the south-central U.S., as a mid-level shortwave trough
moves into the southern Plains. Near this trough, scattered
thunderstorm development will be possible. Moderate deep-layer shear
and instability should be favorable for an isolated severe threat
during the afternoon and evening, mainly from Oklahoma southward
into west-central Texas.

Considering the last few days of the Day 4 to 8 period, recent
models have shown substantial variability from run to run. Scenarios
have been outlined based on model consensus. However, confidence is
low concerning potential outcomes, especially this upcoming weekend.

..Broyles.. 05/09/2026

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ACUS48 KWNS 100844
SWOD48
SPC AC 100842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Sun May 10 2026

Valid 131200Z - 181200Z

...DISCUSSION...
...Wednesday/Day 4 to Friday/Day 6...
An upper-level trough is forecast to move into the eastern U.S. on
Wednesday and become substantially amplified. Ahead of the trough,
enough instability is expected to develop in the central
Appalachians Wednesday afternoon for an isolated severe threat.

On Thursday, a mid-level shortwave ridge is forecast to move through
the central U.S. An axis of instability appears likely to develop in
the Great Plains in the wake of the ridge. Although an isolated
severe threat will be possible along parts of this instability
corridor Thursday afternoon, model forecasts suggest a cap will
minimize convective coverage.

The ridge is forecast to move into the Ohio Valley and Great Lakes
on Friday, as a mid-level shortwave trough moves into the
north-central states. Isolated severe storms could occur ahead of
this trough in the northern Plains and upper Mississippi Valley
Friday afternoon. Additionally, a conditional severe threat could
develop southward into the southern and central Plains, but this
would materialize only if storms can initiate in a somewhat capped
environment.

...Saturday/Day 7 and Sunday/Day 8...
On Saturday and Sunday, a moist and unstable airmass is forecast to
gradually advect northward across the southern and central Plains.
Isolated to scattered storms will be possible each afternoon over
parts of this airmass. However, large-scale ascent is forecast to
remain limited and convective initiation will likely be
mesoscale-driven. For this reason, predictability is low over the
weekend concerning any potential for severe storms.

..Broyles.. 05/10/2026

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ACUS48 KWNS 110820
SWOD48
SPC AC 110818

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0318 AM CDT Mon May 11 2026

Valid 141200Z - 191200Z

...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
At mid-levels, a shortwave ridge is forecast to pass eastward
through the north-central U.S. on Thursday. A shortwave trough is
forecast to move into the Great Plains, with moisture and
instability located in the central Plains. Although most of the
airmass is forecast to be capped during the day, a few storms with
an isolated severe threat will be possible in areas that heat up the
most.

On Friday, a mid-level ridge is forecast to move eastward across the
Great Plains, as a moisture and instability advects northeastward
into the lower to mid Missouri Valley. Isolated to scattered
thunderstorms will be possible within this airmass in the afternoon
and evening. Hail and isolated severe gusts would be the primary
threats.

By Saturday, a wide corridor of moderate instability is forecast to
be in place over the Great Plains. A shortwave trough is forecast to
move into the central U.S. during the afternoon. Ahead of the
shortwave, scattered thunderstorms will be possible from north Texas
northward into Nebraska. Along the western edge of the instability
corridor, steep mid-level lapse rates and moderate deep-layer shear
are forecast. The environment could support large hail, damaging
wind gusts and an isolated tornado threat in the southern and
central Plains where instability, shear and lift are forecast to
become maximized.

...Sunday/Day 7 and Monday/Day 8...
On Sunday, mid-level flow is forecast to be southwesterly over the
central U.S., as a shortwave trough moves into the Great Lakes.
Another shortwave trough is forecast to move into the northern High
Plains. Further south in the southern and central Plains, moderate
to strong instability is forecast to be in place by midday.
Thunderstorm development is expected over parts of this unstable
airmass in the afternoon and evening. Although uncertainty exists
concerning the location of the greatest severe threat, some
solutions suggest potential for a large complex of storms from
eastern Kansas into Missouri. At this time, too much uncertainty
exists for the addition of a severe threat area.

On Monday, a front is forecast to advance southeastward across the
central U.S. Ahead of this front, isolated severe storms will be
possible near an axis of instability in the afternoon and evening.
However, model spread is relatively large concerning the timing of
features at this extended range.

..Broyles.. 05/11/2026

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ACUS48 KWNS 120858
SWOD48
SPC AC 120857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Tue May 12 2026

Valid 151200Z - 201200Z

...DISCUSSION...
...Friday/Day 4 to Sunday/Day 6...
Over the weekend, mid-level flow is forecast to gradually become
southwesterly across the central U.S. In response, low-level
moisture advection will occur in the Great Plains. By Friday
afternoon, a moist and unstable airmass is forecast to be in place
from north Texas into Oklahoma, eastern Kansas and central to
northern Missouri. Isolated severe storms will be possible within
this airmass Friday afternoon and evening.

On Saturday, a dryline is forecast to develop from the far eastern
Texas Panhandle northward into west-central Kansas. To the east of
the dryline, surface dewpoints in the 60s F will contribute to
moderate instability by afternoon. As a mid-level shortwave trough
approaches in the afternoon, scattered thunderstorms are expected to
form to the east of the dryline from western Oklahoma into central
and eastern Kansas. Supercells with large hail, severe wind gusts,
and a tornado threat could develop.

A surge of deeper low-level moisture is expected across the southern
and central Plains on Sunday, as an upper-level trough moves through
the western U.S. In response, a north-to-south corridor of strong
instability is forecast by afternoon from western Oklahoma north and northeastward into central and eastern Kansas. Scattered
thunderstorms are expected within this unstable airmass during the
afternoon and evening. MCS development may occur in the evening as a
complex moves northeastward from the central Plains into the mid
Missouri Valley. Supercells with large hail, severe wind gusts and a
tornado threat will be possible.

...Monday/Day 7 and Tuesday/Day 8...
An upper-level trough is forecast to move across the north-central
U.S. on Monday, as a cold front advances southeastward into the mid
Mississippi Valley, Ozarks and southern Plains. Scattered to
numerous thunderstorms are forecast to form ahead of the front in
the afternoon. At this time, model forecasts suggest that
instability and deep-layer shear will be strong enough for severe
storms across a broad area. However, uncertainty exists concerning
the location of the front Monday afternoon. A severe threat area may
be needed in later Outlooks, once confidence increases concerning
the timing of the front.

On Tuesday, the cold front is forecast to move southward into north
Texas and the southern Ozarks. An isolated severe threat could
develop ahead of the front in the afternoon and evening. However,
uncertainty is substantial at this extended range.

..Broyles.. 05/12/2026

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ACUS48 KWNS 130859
SWOD48
SPC AC 130857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Wed May 13 2026

Valid 161200Z - 211200Z

...DISCUSSION...
...Saturday/Day 4 to Monday/Day 6...
At mid-levels, a shortware trough will move eastward across the
western U.S. on Saturday, as flow becomes west-southwesterly over
much of the central U.S. In response, moisture advection is forecast
to increase over the central U.S. as a pocket of 65 to 70 F
dewpoints moves northward into the lower and mid Missouri Valley. A
dryline is forecast on the western edge of the moist airmass.
Isolated to scattered storms appear likely to initiate to the east
of the dryline in the afternoon. Additional storms may form eastward
across the lower to mid Missouri Valley. Moderate deep-layer shear
is forecast over the instability axis, which should support a
potential for supercells with large hail and severe wind gusts.

On Sunday, an upper-level trough is forecast to develop over the
western U.S. Mid-level flow is expected to become southwesterly over
the Great Plains, where model forecasts show a surge of low-level
moisture. In response, surface dewpoints are forecast to increase
into the mid to upper 60s F over much of the north-central U.S. A
series of subtle shortwave troughs moving through the Great Plains
will likely support scattered to numerous thunderstorms in the
afternoon and evening. The greatest severe threat may develop over
eastern Nebraska and western Iowa, along the northern edge of a
low-level jet. A potential for supercells with large hail, wind
damage and a tornado threat is expected.

On Monday, the upper-level trough is forecast to move across the
Intermountain West, as multiple shortwave impulses move
northeastward across the Great Plains. A cold front is forecast to
move southeastward across the central U.S. Ahead of the front,
surface dewpoints in the lower to mid 70s F are forecast to be in
place by afternoon. In response, strong instability is expected to
develop in parts of the moist airmass. In addition, a mid-level jet
is forecast to eject northeastward across the central U.S. Moderate
to strong deep-layer shear associated with the jet will support a
potential for severe storms across a broad area from the southern
Plains northeastward into the Upper Midwest. Supercells and bowing
line segments with large hail, severe wind gusts and tornadoes will
be possible.

...Tuesday/Day 7 and Wednesday/Day 8...
On Tuesday and Wednesday, a cold front is forecast to move from the
Upper Midwest southeastward into the Appalachians. A moist and
unstable airmass will likely be in place ahead of the front, with
scattered to numerous thunderstorms likely developing each afternoon
and evening. The greatest severe threat could materialize over the
mid Mississippi and lower Ohio Valley on Tuesday, and in the
Northeast on Wednesday, adjacent to a mid-level jet passing through.
However, uncertainty is substantial at this time concerning the
timing of the upper-level trough and cold front.

..Broyles.. 05/13/2026

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ACUS48 KWNS 140903
SWOD48
SPC AC 140901

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Thu May 14 2026

Valid 171200Z - 221200Z

...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/SUN...D5/MON...

...DISCUSSION...
...Sunday/Day 4 and Monday/Day 5...
An upper-level trough is forecast to move eastward across the
Intermountain West on Sunday, as a subtle shortwave trough moves
northeastward across the Great Plains. Ahead of the trough a moist
and unstable airmass is forecast across much of the Great Plains
eastward into the Mississippi Valley. Scattered elevated strong
thunderstorms will be possible early in the day from the northern
Plains eastward into the upper Mississippi Valley. Southward into
the central Plains and mid Missouri Valley, strong surface heating
is forecast. Some models suggest MLCAPE could peak in the 3000 to
4000 J/kg range. In addition, a broad 40 to 50 knot low-level jet is
forecast to strengthen late Sunday afternoon. This, combined with
moderate to strong deep-layer shear over much of the moist sector
will be favorable for severe storms potentially over a large area. A
severe weather outbreak will be possible from the afternoon and
evening into the early overnight period. The setup appears favorable
for supercells with tornadoes, large to very large hail and wind
damage.

On Monday, model forecasts eject a negatively-tilted upper-level
trough into the central Plains. Ahead of the trough, a moist and
unstable airmass is forecast to be located from the southern and
central Plains northeastward into the Upper Midwest. A mid-level jet
is forecast to also eject northeastward across the central Plains as
a broad low-level jet strengthens during the late afternoon.
Thunderstorm development is expected along the western edge of the
airmass near a dryline over west-central Kansas and southeast
Nebraska. Thunderstorms that move into the strong low-level flow in
the late afternoon and early evening will have potential to be
supercells with large to very large hail, and tornadoes. Severe wind
gusts will also be possible. A severe weather outbreak will be
possible from Monday afternoon into evening and overnight period.

...Tuesday/Day 6 to Thursday/Day 8...
On Tuesday, mid-level southwesterly flow is forecast over the
central U.S., with a cold front moving southeastward through the
central Plains and Upper Midwest. Ahead of this front, surface
dewpoints from the mid 60s to the lower 70s F are expected to
contribute to moderate to strong instability. Thunderstorm
development with a severe threat will be possible along and ahead of
the front during the afternoon and evening from the northern part of
the southern Plains northeastward into the mid Mississippi Valley.

On Wednesday and Thursday, the cold front is forecast to move slowly southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon and
evening. However, uncertainty concerning the exact location of the
front is substantial at this extended range.

..Broyles.. 05/14/2026

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ACUS48 KWNS 150903
SWOD48
SPC AC 150901

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Fri May 15 2026

Valid 181200Z - 231200Z

...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/MON...

...DISCUSSION...
...Monday/Day 4...
A severe weather outbreak will be possible from Monday afternoon
into the evening and overnight period. On Monday, the western trough
will take on a negative tilt before ejecting across the central
Plains, with strong southwesterly flow aloft overspreading the
region. This will result in strong lee cyclone development across
western Kansas. A surface cold front will extend northward to a
secondary surface low across the upper Midwest. A dryline will
extend southward across portions of western Kansas into western
Oklahoma. Numerous thunderstorms are expected to develop along and
ahead of the cold front and further south along the dryline Monday
afternoon and evening from Nebraska into central Kansas. Given the
volatile air mass ahead of these features, with moderate to strong
instability and strengthening deep layer shear, initial development
will likely be supercellular. Initial supercells will pose risk of
all hazards including large to very large hail, damaging wind, and
tornadoes. As the southwesterly low-level jet increases into the
evening, large clockwise enhancement of low-level hodographs across
portions of central Kansas into northern Oklahoma may lead to an
increasing risk for strong to intense tornadoes. Additional
thunderstorm development will spread in tandem with the cold front
from the central Plains to the upper Midwest through the evening,
with potential for more widespread damaging wind and a few tornadoes
(some of which may be strong).

...Tuesday/Day 5 to Thursday/Day 7...
Severe potential is expected to continue D5/Tuesday as the cold
front extends from the upper Midwest to southern Plains. Strong to
moderate instability ahead of the front will continue to support
severe storms from the northern part of the southern Plains
northeastward into the mid Mississippi Valley. Trends are for the
front to shift eastward faster than originally expected, and as such probabilities were shifted eastward with this update. Strong to
severe storms may extend further north into the northeast and Great
Lakes Region.

On Wednesday and Thursday, the cold front is forecast to move
southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon and
evening. However, uncertainty concerning the exact location of the
front is substantial at this extended range.

..Thornton.. 05/15/2026

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ACUS48 KWNS 160859
SWOD48
SPC AC 160858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Sat May 16 2026

Valid 191200Z - 241200Z

...DISCUSSION...
...D4/Tuesday...
Severe potential is expected to continue D4/Tuesday as the cold
front extends from the upper Midwest to southern Plains. Moderate to
strong instability ahead of the front will continue to support
severe storms with potential for damaging wind and large hail from
the northern part of the southern Plains northeastward into the
Great Lakes Region. Probabilities were shifted eastward and
northward with this update in alignment with continued trends for
the timing/placement of the cold front.

... D5/Wednesday - D8/Saturday...
On Wednesday and Thursday, the cold front is forecast to move
southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon. However,
strongest upper-level flow becomes displaced to the north from the
better instability, which will reside along and south of the front
across the southeastern US. This leads to low confidence in any
organized severe threat.

D6/Thursday through D8/Saturday, moist southerly return flow will
begin across the southern/central Plains into the weekend. Overall,
forcing for ascent will remain limited with generally weak flow and
height rises across the Plains. Areas of thunderstorms may continue
from the far southern Plains into the Southeast, but confidence in a
more focused corridor of severe weather threat remains low at this
time.

..Thornton.. 05/16/2026

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ACUS48 KWNS 170856
SWOD48
SPC AC 170854

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Sun May 17 2026

Valid 201200Z - 251200Z

...DISCUSSION...
... D4/Wednesday - D8/Sunday...
On D4/Wednesday and D5/Thursday, a cold front will move
southeastward across the southern Plains and mid Mississippi Valley,
extending east-northeastward into the Mid-Atlantic. A severe threat
could develop along and ahead of the front each afternoon. However,
strongest upper-level flow becomes displaced to the north from the
better instability, which will reside along and south of the front
across the southeastern US. There will be some potential for high
based thunderstorm development within the upslope regime across New
Mexico into far western Texas D4/Wednesday, with potential for large
hail. Overall, there is low confidence in a widespread/organized
severe threat.

D5/Thursday through D8/Sunday, moist southerly return flow will
begin across the southern/central Plains into the weekend. It is
likely that the cold front will stall becoming a diffuse stationary
boundary extending across the southern Plains into the Southeast,
with thunderstorm activity along and south of the boundary each day.
Overall, forcing for ascent will remain limited with generally weak
flow and height rises across the Plains. Confidence in a more
focused corridor of severe weather threat remains low at this time.

..Thornton.. 05/17/2026

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ACUS48 KWNS 180846
SWOD48
SPC AC 180844

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Mon May 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
...D4/Thursday - D5/Friday...
On D4/Thursday, a stationary front will extend across the southern
Plains and mid Mississippi Valley and east to the Carolinas.
A few stronger thunderstorms may develop south of this boundary,
however, the strongest upper-level flow will be displaced to the
north, limiting confidence in a more organized severe threat.

Moist southerly return flow will begin across the southern/central
Plains into the weekend. Modest westerly flow across the dryline on
D5/Friday may support some potential for severe storms. Overall,
forcing for ascent will remain limited and there is low confidence
in including a severe risk area at this time.

...D6/Saturday-D8/Monday...
Through the end of the extended period, height rises are expected
across the central US as a high amplitude ridge settles in from the
west. While moisture will continue to move northward into the
central/northern Plains, generally weak flow and subsidence will
keep severe potential low.

..Thornton.. 05/18/2026

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ACUS48 KWNS 181400
SWOD48
SPC AC 181358

Day 4-8 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0858 AM CDT Mon May 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
...D4/Thursday - D5/Friday...
On D4/Thursday, a stationary front will extend across the southern
Plains and mid Mississippi Valley and east to the Carolinas.
A few stronger thunderstorms may develop south of this boundary,
however, the strongest upper-level flow will be displaced to the
north, limiting confidence in a more organized severe threat.

Moist southerly return flow will begin across the southern/central
Plains into the weekend. Modest westerly flow across the dryline on
D5/Friday may support some potential for severe storms. Overall,
forcing for ascent will remain limited and there is low confidence
in including a severe risk area at this time.

...D6/Saturday-D8/Monday...
Through the end of the extended period, height rises are expected
across the central US as a high amplitude ridge settles in from the
west. While moisture will continue to move northward into the
central/northern Plains, generally weak flow and subsidence will
keep severe potential low.

..Thornton.. 05/18/2026

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ACUS48 KWNS 190901
SWOD48
SPC AC 190900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Tue May 19 2026

Valid 221200Z - 271200Z

...DISCUSSION...
...D4/Friday...
Moist southerly return flow will begin across the southern/central
Plains into the weekend. Modest westerly flow aloft across the
dryline on D4/Friday may support potential for severe storms.
Guidance shows disagreement in the location of the dryline, with
some guidance depicting the dryline back in the OK/TX Panhandle and
others with a further east dryline into western Oklahoma. Forecast
soundings show limited inhibition by the afternoon, with strong
daytime heating and temperatures warming into the mid to upper 80s.
Steep low to mid-level lapse rates are also noted, with moderate to
strong instability ahead of the dryline. Given weak inhibition and
modest mid-level flow, convective initiation is possible by the
afternoon. Shear profiles are marginally sufficient to support
organized storms, with a mix of multi-cell and supercell modes. A
15% area was added with this outlook where confidence is greater in
convection occurring.

...D5/Saturday-D8/Tuesday...
Through the end of the extended period, height rises are expected
across the central US as a high amplitude ridge settles in from the
west. While moisture will continue to move northward into the
central/northern Plains, generally weak flow and subsidence will
keep severe potential low.

..Thornton.. 05/19/2026

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ACUS48 KWNS 200858
SWOD48
SPC AC 200856

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Wed May 20 2026

Valid 231200Z - 281200Z

...DISCUSSION...
Severe potential will remain low through the extended period. Weak
troughing will continue across the central Plains through the
weekend before height rises begin across the central US with a high
amplitude ridge settling in from the west. This pattern will remain
in place through early to middle of next week. Slow moisture return
will be ongoing across much of the Plains into the Midwest with
occasional rounds of widespread rainfall and thunderstorms, but
generally weak flow and subsidence will keep organized storm
potential low through D8/Wednesday.

..Thornton.. 05/20/2026

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ACUS48 KWNS 210849
SWOD48
SPC AC 210847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Thu May 21 2026

Valid 241200Z - 291200Z

...DISCUSSION...
Severe potential will remain low through the beginning of the
extended period. Weak troughing will continue across the central
Plains D4/Sunday before height rises begin across the central US
with a high amplitude ridge settling in from the west D5/Monday.
This pattern will remain in place through early next week. Slow
moisture return will be ongoing across much of the Plains into the
Midwest with occasional rounds of widespread rainfall and
thunderstorms, but generally weak flow and subsidence will keep
organized storm potential low.

By the midweek, a trough is progged to begin deepening across the
Pacific Northwest. As the upper low slowly shifts eastward, stronger
flow will overspread the Intermountain West into the Northern
Rockies, resulting in strengthening lee troughing across the
central/northern Plains D6/Tuesday and D7/Wednesday. Moisture
advection will spread northward amid strengthening southerly flow
across the central/northern Plains. While there are some differences
in the placement of upper-level and surface features, it is possible
that severe chances will return across portions of northern High
Plains. For now, confidence in exact corridors remains low given
model guidance differences.

..Thornton.. 05/21/2026

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ACUS48 KWNS 220903
SWOD48
SPC AC 220901

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Fri May 22 2026

Valid 251200Z - 301200Z

...DISCUSSION...
Severe potential will remain low D4/Monday. Height rises begin
across the central US with a high amplitude ridge settling in from
the west. Slow moisture return will be ongoing across much of the
Plains into the Midwest with widely scattered areas of rainfall and thunderstorms. A few strong to marginally severe storms will be
possible, but generally weak flow and subsidence will keep organized
storm potential low.

A trough is progged to begin deepening across the Pacific Northwest
D5/Tuesday into D6/Wednesday. As the upper low slowly shifts
eastward, stronger flow will overspread the Intermountain West into
the Northern Rockies, resulting in strengthening lee troughing
across the central/northern Plains. Moisture advection will spread
northward amid strengthening southerly flow across the
central/northern Plains. There remains uncertainty in the northward
and westward extent of moisture return and in progression of the
western trough. Severe storms may occur each day across some portion
of the northern and northern/central High Plains. For now,
confidence in exact corridors remains low.

By D7/Thursday-D8/Friday, guidance suggests the western low becomes
cut off and slowly wobbles towards the Great Basin before becoming
absorbed back into the northern stream. This is likely due to
continued high amplitude ridging across the central US. Some severe
potential may extend into the eastern US as a cold front shifts
southward as flow enhances in the trough across Quebec in the D7-D8
period.

..Thornton.. 05/22/2026

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ACUS48 KWNS 230855
SWOD48
SPC AC 230853

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0353 AM CDT Sat May 23 2026

Valid 261200Z - 311200Z

...DISCUSSION...
A trough will deepen and shift eastward across the Pacific Northwest D4/Tuesday-D5/Wednesday. As the upper low slowly shifts eastward,
stronger flow will overspread the Intermountain West into the
Northern Rockies which will result in strengthening lee troughing
across the central/northern Plains. Moisture advection will spread
northward with the strengthening southerly flow across the
central/northern Plains. Severe storms may occur each day across
some portion of the northern and northern/central High Plains. In
addition, strengthening southern stream flow may bring stronger
storms across the Sierra Madre which may bring severe potential into
portions of far southern Texas. For now, confidence in exact
corridors of greater severe potential remains low.

By D6/Thursday-D8/Saturday, guidance suggests the western low
becomes cut off and slowly wobbles towards the Great Basin before
becoming absorbed back into the northern stream, likely due to the
high amplitude ridging across the central. Some severe potential may
extend into the eastern US as a cold front shifts southward as flow
enhances in the trough across Quebec in the D6-D7 period.

..Thornton.. 05/23/2026

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ACUS48 KWNS 240902
SWOD48
SPC AC 240900

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Sun May 24 2026

Valid 271200Z - 011200Z

...DISCUSSION...
The western US trough will shift southward into the Great Basin on
D4/Wednesday with strengthening westerly flow overspreading the
southwestern US. The axis of the central US ridge will shift
eastward, with heights continuing to rise across portions of the central/northern Plains. A few stronger storms may be possible
across portions of central/eastern Montana. Overall, confidence is
low in any areas of organized severe potential. Widely scattered
thunderstorm activity will be possible from the Southern/Central
Plains to the southeastern US. Generally weak flow should keep
organized severe potential low. The exception may be across far
western Texas where modest mid-level flow will continue, though
large scale forcing for ascent will decrease from D3/Tuesday.

For the D5/Thursday through D6/Friday period, ensemble guidance
suggests the western low will shift northward again and phase with
the northern jet stream. There is low confidence in chances for
strong to severe storms, pending details on moisture, across the
northern Rockies into the central/northern high Plains as lee
troughing strengthens. Some severe potential may also extend into
the eastern and southeastern US as a cold front shifts southward as
flow enhances in the trough across Quebec from D6/Friday to
D7/Saturday.

..Thornton.. 05/24/2026

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