ACUS01 KWNS 281255
SWODY1
SPC AC 281253

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0753 AM CDT Tue Jul 28 2026

Valid 281300Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC AND CAROLINAS...

...SUMMARY...
Thunderstorms capable of severe wind gusts and a tornado threat are
expected today from parts of the Mid-Atlantic southward into the
Carolinas. A few severe wind gusts and hail may also occur this
afternoon and evening across parts of the central High Plains.

...Mid-Atlantic/Carolinas and southern Appalachians...
A loosely organized band of storms, with some semi-discrete
storms/prior supercell on its southwestern flank around sunrise,
will continue to progress east-southeastward across the Cumberland
Plateau toward/across the Appalachians spine early today. Some
severe risk may exist this morning with the aforementioned storms on
the southwest flank including along the Kentucky/West
Virginia/Virginia border vicinity, but storm-associated cloud cover
and precipitation will otherwise be an important and somewhat
uncertain factor for destabilization with northeastward extent
regionally later today.

The region will be influenced by some additional large-scale
amplification of the upper trough along the East Coast, with a belt
of notably strong (45-55 kt around 500 mb) northwesterly flow aloft,
as sampled by upstream 12z observed RAOBs from the likes of
Wilmington OH and Pittsburgh PA, that is expected to spread
southeastward toward the region today. A moist air mass will persist
ahead of the east-southeastward-moving cold front, with the
strongest destabilization across the southern Appalachians vicinity
and Carolinas. Recovery/destabilization is generally expected across
Virginia in the wake of the early day convection, allowing for
probable severe-storm development into mid/late afternoon. Severe
storms may occur farther north across the Mid-Atlantic within a more
narrow warm sector.

Ample deep-layer shear and moderate low-level shear/SRH will support
a combination of supercells and organized line segments, with a more
discrete mode, and longer duration thereof, expected with the
southwesternmost extent of storms regionally from southern Virginia
into the Carolinas/southern Appalachians. Some tornado potential
will exist aside from a more prevalent damaging wind risk this
afternoon and evening as storms spread toward coastal areas.

...Central High Plains...
A ridge-peripheral low-amplitude/subtle shortwave trough will
influence scattered thunderstorm development later today.
Thunderstorms are expected to form in the higher terrain and drift
eastward into the lower elevations. Moderate buoyancy across the
High Plains and upwards of 30-40 kt (stronger northward regionally)
effective shear will support sustained storms. Steep low-level lapse
rates and surface-temperature dewpoint spreads near 30 degrees F
will support a potential for isolated severe wind gusts, aside from
some hail this afternoon and evening.

..Guyer/Wendt.. 07/28/2026

$$
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ACUS01 KWNS 291247
SWODY1
SPC AC 291246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Wed Jul 29 2026

Valid 291300Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHEAST AND NORTHERN HIGH PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon and evening in the northern Plains. Severe wind gusts will
also be possible today across southern Georgia and northern Florida,
as well as the Great Basin/northern Intermountain West.

...Southeast States...
Near the base of the extensive eastern CONUS trough, a cold front
will slowly spread southward/stall regionally, with a moist and
unstable air mass to its south. Surface dewpoints in the 70s F will
contribute to an axis of strong instability by afternoon, with
MLCAPE likely reaching 3000+ J/kg with steep low-level lapse rates.
Damaging winds will be possible with the stronger storms, which
could include the development of some semi-organized clusters into
late afternoon/early evening.

...Northern Plains/Upper Midwest...
An approaching disturbance and weak height falls will develop into
the region later today, interfacing with an east-southeastward
moving front and somewhat sharpening the regional lee trough ahead
of it. Surface dewpoints in the mid to upper 50s F will contribute
to moderate instability as surface temperatures diurnally warm.
Low-level convergence along the front/lee trough will aid convective initiation, with scattered thunderstorms moving eastward
across the western Dakotas during the late afternoon and early
evening. Large hail can be expected, and the high-based storms will
be capable of severe-caliber wind gusts, especially if storms
aggregate and cluster into the evening.

Farther east, a more conditional-type threat will exist diurnally
into northern Minnesota within a very unstable environment, but it
is a bit more probable that widely scattered storms develop into the
region tonight. If so, a few severe storms capable of wind/hail could occur.

...Great Basin/northern Intermountain West...
A northeastward-transitioning shortwave trough and speed max, along
with diurnal heating, will influence thunderstorm development across
the region, including portions of southern/eastern Idaho and nearby
portions of northeast Nevada, northern Utah and southwest Montana.
Modestly enhanced mid-level winds and sufficient buoyancy/steep
lapse rates will support the potential for a few severe storms
capable of severe-caliber wind gusts and possibly some hail.

...Coastal southern New England...
Bands of semi-organized convection will move toward the coast
through the afternoon, preceding the offshore surface low/triple
point. Some stronger storms could materialize toward the coast with
gusts given the strengthening low-level winds, but current thinking
is the primary warm sector should remain offshore and limit the
severe potential.

..Guyer/Wendt.. 07/29/2026

$$
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ACUS01 KWNS 041237
SWODY1
SPC AC 041235

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 AM CDT Tue Aug 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR SOUTHEAST ARIZONA...

...SUMMARY...
Scattered severe wind gusts are possible across southeast Arizona
during the late afternoon and evening.

...Southeast Arizona...
A flattened mid to upper-level ridge over the Desert Southwest will
feature a moderate belt of easterlies across Sonora into far
southern portions of NM and AZ. A seasonably moist airmass will
undergo strong heating and result in moderate buoyancy by mid
afternoon (1000-2000 J/kg MLCAPE) per RAP/NAM forecast soundings.
Initially widely scattered storm development over the higher terrain
will gradually move west across southeast AZ during the late
afternoon and evening. Steep 700-500 mb lapse rates (around 8 deg
C/km) atop very steep low-level lapse rates ahead of this activity
will support ample evaporative cooling potential with the stronger
thunderstorm cores. The resultant microbursts and associated
outflow will yield a risk for 60-80 mph gusts as storms congeal into
a small cluster or two.

...Sangre de Cristos and adjacent plains...
A local maximum in buoyancy is depicted by model guidance near the
Raton Mesa by mid-late afternoon where widely scattered storms will
likely develop. Some of the CAMs show this activity moving
southeast into parts of the OK-TX Panhandles during the early
evening with an isolated risk for severe gusts. Marginally severe
hail is possible with the stronger cores.

...Western Carolinas...
A mid-level low will remain over northern Georgia today. To the
east of the low, an axis of moderate instability is forecast to
develop over the western Carolinas by afternoon. Warming surface
temperatures in the higher terrain will result in scattered
convective initiation across the southern Appalachians. As
instability peaks and low-level lapse rates become steep in the
afternoon, an isolated wind-damage threat is expected to develop in
the western Carolinas.

..Smith/Bentley.. 08/04/2026

$$
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RETRY

ACUS01 KWNS 041237
SWODY1
SPC AC 041235

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 AM CDT Tue Aug 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR SOUTHEAST ARIZONA...

...SUMMARY...
Scattered severe wind gusts are possible across southeast Arizona
during the late afternoon and evening.

...Southeast Arizona...
A flattened mid to upper-level ridge over the Desert Southwest will
feature a moderate belt of easterlies across Sonora into far
southern portions of NM and AZ. A seasonably moist airmass will
undergo strong heating and result in moderate buoyancy by mid
afternoon (1000-2000 J/kg MLCAPE) per RAP/NAM forecast soundings.
Initially widely scattered storm development over the higher terrain
will gradually move west across southeast AZ during the late
afternoon and evening. Steep 700-500 mb lapse rates (around 8 deg
C/km) atop very steep low-level lapse rates ahead of this activity
will support ample evaporative cooling potential with the stronger
thunderstorm cores. The resultant microbursts and associated
outflow will yield a risk for 60-80 mph gusts as storms congeal into
a small cluster or two.

...Sangre de Cristos and adjacent plains...
A local maximum in buoyancy is depicted by model guidance near the
Raton Mesa by mid-late afternoon where widely scattered storms will
likely develop. Some of the CAMs show this activity moving
southeast into parts of the OK-TX Panhandles during the early
evening with an isolated risk for severe gusts. Marginally severe
hail is possible with the stronger cores.

...Western Carolinas...
A mid-level low will remain over northern Georgia today. To the
east of the low, an axis of moderate instability is forecast to
develop over the western Carolinas by afternoon. Warming surface
temperatures in the higher terrain will result in scattered
convective initiation across the southern Appalachians. As
instability peaks and low-level lapse rates become steep in the
afternoon, an isolated wind-damage threat is expected to develop in
the western Carolinas.

..Smith/Bentley.. 08/04/2026

$$
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ACUS01 KWNS 092000
SWODY1
SPC AC 091959

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sun Aug 09 2026

Valid 092000Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE MIDWEST INTO THE OHIO VALLEY...

...SUMMARY...
Scattered damaging winds are possible today into this evening from
southern Wisconsin eastward across parts of northern Illinois,
southern Lower Michigan, northwest Ohio, and northern Indiana.
Damaging wind and hail may also occur across portions of the Dakotas
tonight.

...20Z Update...
The main changes made to the outlook were to remove the Slight Risk
and more broadly expand Marginal Risk severe probabilities across
the central/northern Plains. CAM guidance has shown appreciable
uncertainty regarding storm coverage in this region, and trends in
model output continue to show sparse coverage. Nonetheless,
widespread 2000+ J/kg MLCAPE amid 50+ kts of effective bulk shear
may support a couple of severe multicells or supercells should any
storms manage to become sustained this afternoon or evening. The
Slight Risk along/south of the Great Lakes was expanded slightly
eastward into northern OH to account for some boundary layer
destabilization ahead of an approaching MCS, where a few damaging
gusts are possible.

Otherwise, the previous forecast remains on track, with only minor
changes made to the severe/thunder probabilities to account for the
latest observations and guidance consensus.

..Squitieri.. 08/09/2026

.PREV DISCUSSION... /ISSUED 1056 AM CDT Sun Aug 09 2026/

...Midwest...
A persistent cluster of thunderstorms over southern WI appears
likely to continue southeastward through much of the day into parts
of IL/MI/IN and eventually OH. This activity will track near a
NW-SE oriented baroclinic zone, with dewpoints in the lower 70s to
the south. Eventually, low-level lapse rates will become
sufficiently steep to support damaging wind gusts along the leading
edge of the storms. Later tonight, strengthening southwesterly
low-level winds will enhance warm advection and lift over parts of
IL/IN, potentially leading to another round of strong/severe storms
capable of damaging winds and hail after 06z.

...Dakotas...
12z model guidance continues to decrease the confidence in overnight
severe storms, with some CAM solutions showing no thunderstorms.
Therefore have made the SLGT area smaller and focused where there is
highest confidence in isolated storms. Forecast soundings continue
to indicate steep mid-level lapse rates and strong deep shear,
providing a conditional risk of supercells if convection can be
sustained.

...AZ...
Thunderstorms are once again predicted to form along the Rim and
track westward toward the PHX metro area this evening. The strength
of the steering flow, instability, and mid-level moisture all appear
favorable for a severe risk. However, mesoscale details of the
evolution of the storms over high terrain will dictate the eventual
risk.

$$


--- ScorpioWeb v0.38a (Linux/x86_64)
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ACUS01 KWNS 301216
SWODY1
SPC AC 301214

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0714 AM CDT Sun Aug 30 2026

Valid 301300Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PARTS OF THE DAKOTAS...

...SUMMARY...
Severe storms capable of damaging wind gusts are possible across
portions of the northern Plains this afternoon and evening.

...MT/ND/SD...
Morning water vapor loop shows a strong upper trough over ID
tracking east-northeastward. This system will emerge onto the
Plains of eastern MT/western Dakotas by late afternoon today, when
strong heating will result in a corridor of surface temperatures
near 90F along the MT/ND border ahead of an approaching cold front. Thunderstorms will intensify in vicinity of this front through the
afternoon, tracking quickly eastward into parts of western/central
ND/SD by 00z. Morning CAM solutions suggest storms will organize
into a line with the risk of severe wind gusts. Given the strength
of the low and mid-level flow near the front, that scenario seems
plausible. Therefore have added a SLGT risk to parts of this
region.

...CO/KS/NE...
South of the primary severe threat, a secondary area of concern will
develop this afternoon as storms develop over the mountains of
central CO and spread eastward into the Plains. This activity will
be high-based and in a weakly unstable environment. Nevertheless,
strong outflow winds will be possible with the activity, spreading
eastward into western NE and northwest KS during the evening.

...UT/Western CO...
Considerable low-level moisture will remain over UT today, leading
to another round of strong thunderstorms this afternoon. Deep-layer
shear remains sufficient for rotating storms capable of damaging
wind gusts and hail. Activity should spread into western CO by
early evening before weakening.

..Hart/Broyles.. 08/30/2026

$$
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ACUS01 KWNS 011213
SWODY1
SPC AC 011212

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0712 AM CDT Tue Sep 01 2026

Valid 011300Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
OVER PARTS OF THE NORTHEAST STATES...AND THIS EVENING OVER THE
CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST....

...SUMMARY...
Scattered strong to severe storms are possible over the central
Plains and Midwest, as well as parts of New York, Pennsylvania and
New Jersey.

...Northeast...
A broad upper ridge remains in place over the Mid MS/TN Valleys,
with northwest flow aloft affecting the northeast US and
Mid-Atlantic states. The main baroclinic zone in this region
currently extends from central NY into southern New England, with
dewpoints in the mid-upper 60s along and south of the boundary. This
air mass is expected to destabilize through the day as temperatures
warm through the 80s, leading to a zone of strong instability
(MLCAPE of 2500+ J/kg) over parts of PA/NY/NJ. Ongoing convection
may delay daytime heating, but eventually strong storms are expected
to form in this region, spreading southeastward through the late
afternoon and evening. Damaging winds are the primary concern,
although some hail and a tornado or two cannot be ruled out. A lack
of a more obvious upper feature to aid in large-scale forcing may
limit the overall coverage of severe storms.

...SD/NE/MN/IA...
A shortwave trough currently over western CO will track quickly
northeastward and affect the central Plains by late afternoon.
Strong heating and a moist air mass will yield moderate CAPE over
parts of SD/NE. Low-level warm advection and diurnal heating will
lead to scattered thunderstorm development over central SD by late
afternoon. Initial supercell storms are expected, capable of
damaging winds, large hail, and perhaps a tornado. Storms are
expected to become more numerous during the evening and grow upscale
into bowing structures, with a damaging wind risk tracking eastward
into parts of southern MN and perhaps northern IA. Some guidance
suggests storms will maintain some damaging wind risk into central
WI overnight.

...Southwest LA/Southeast TX...
Tropical Storm Eduardo is expected to strengthen today off the
immediate LA/TX coast and move inland this afternoon and evening.
Models continue to show limited discrete convection in the northeast
quadrant of the system, suggested a rather low tornado risk today. Nevertheless, given the potential for rapid strengthening around the
time of landfall, have opted for a small 2% tornado risk area for a
few hours this evening.

..Hart/Dean.. 09/01/2026

$$
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ACUS01 KWNS 021225
SWODY1
SPC AC 021223

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0723 AM CDT Wed Sep 02 2026

Valid 021300Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHEAST STATES...AND ACROSS PARTS OF MONTANA...

...SUMMARY...
Severe thunderstorms are possible across portions of the eastern
Great Lakes to the Mid-Atlantic today and tonight. Damaging wind
gusts are the main threat, though some large hail and a few
tornadoes may also occur. Scattered severe gusts and more sporadic
occurrences of large hail appear possible from the northern Rockies
into northern High Plains today into night.

...Northeast States...
A complex but potentially active convective day is in store for
parts of the northeast US today. A fast-moving MCS and associated
mid-level shortwave trough is over Lake Michigan. This system is
forecast to track rapidly eastward across Lower MI and southwest ON
this morning before emerging into western NY/PA this afternoon. A
consensus of overnight CAM solutions indicate this will be the focus
for strong-severe thunderstorms that track east-southeastward during
the afternoon and evening toward the Mid-Atlantic coast. Ample
low-level moisture is present in this corridor. This along with
daytime heating well into the 80s and steep low-level lapse rates
will favor damaging wind gust potential in the strongest storms. A
north-south surface boundary is expected to lie from central NY into east-central PA this afternoon, where low-level shear will be
locally enhanced to pose some risk of a few tornadoes.

The primary uncertainty for a more widespread severe event today is
the presence of considerable morning convection currently over
northwest PA and western NY. These storms are well-ahead of the
main forcing feature, and decrease confidence in significant
destabilization over the primary risk area this afternoon. These
early storms may pose a damaging wind and hail risk through the day,
especially after a few hours of heating.

...MT...
Scattered high-based thunderstorms are expected to develop over the
mountains of southwest MT this afternoon. Strong winds aloft and
steep low-level lapse rates will aid in the risk of damaging wind
gusts as the activity spreads northeastward through the early
evening.

...CO/WY...
Scattered afternoon thunderstorms are expected to develop over the
mountains of northern/western CO and southern WY. This activity
will spread northeastward into eastern WY/western NE where
inverted-v thermodynamic profiles are expected with 40-50 t-td
spreads. This may result in locally damaging wind gusts.

..Hart/Dean.. 09/02/2026

$$
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ACUS01 KWNS 031213
SWODY1
SPC AC 031212

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0712 AM CDT Thu Sep 03 2026

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
TONIGHT ACROSS PARTS OF THE SOUTHERN GREAT LAKES INTO MID ATLANTIC
AND PARTS OF THE NORTHERN GREAT PLAINS...

...SUMMARY...
Scattered strong thunderstorm development is likely today through
tonight, perhaps including a few organizing clusters, posing a risk
for severe wind and hail across parts of the southern Great Lakes
into Mid Atlantic and portions of the northern Great Plains into
Upper Midwest.

...PA to Delmarva...
A broad upper ridge remains over the TN Valley, with fast zonal flow
stretching across the Great Lakes into the Mid-Atlantic region.
Multiple clusters of thunderstorms are ongoing this morning over
western PA and northern MD. These storms will progress
southeastward today across an air mass affected by storms last
evening, where there is uncertainty how much destabilization can
occur. Damaging winds will be possible in those areas where
sufficient heating can occur, especially by early afternoon.

...WI to PA...
A common scenario in recent CAM solutions is that a mid-level speed
max associated with convection over MN/IA will track across WI and
into Lower MI by mid/late afternoon. Morning convection will result
in an outflow boundary from southeast WI into southern Lower MI,
likely providing the focus for rapid afternoon thunderstorm
development. Ample low-level moisture/CAPE and favorable westerly
flow aloft suggest an initial risk of supercells, but increasing
linear organization with time. Storms will track into northern
IN/OH by late afternoon, and eventually into western NY/PA this
evening. Damaging wind gusts are the primary concern with this
activity.

...ND/MN...
Morning water vapor imagery suggests a strong shortwave trough
lifting northeastward across WY. This feature will move into the
Dakotas today, aiding the development of intense thunderstorms over
eastern ND by mid-afternoon. Initial supercells will be capable of
large hail and a tornado or two. Activity will likely persist
through much of the evening, tracking eastward across parts of
northern/central MN and perhaps into northern WI. Damaging winds
and hail would be the main concerns during that period.

..Hart/Dean.. 09/03/2026

$$
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ACUS01 KWNS 041257
SWODY1
SPC AC 041255

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 AM CDT Fri Sep 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
GREAT LAKES INTO THE MID-ATLANTIC STATES...

...SUMMARY...
A couple of organized clusters of thunderstorms may develop across
the southern Great Lakes and mid/upper Ohio Valley today through
tonight, accompanied by the risk for damaging wind gusts. More
widely scattered strong thunderstorms east of the Blue Ridge may
also pose potential for damaging wind gusts this afternoon and evening.

...Southern Great Lakes into Mid Atlantic...
Early-morning satellite imagery shows a deep cyclone over the
Pacific Northwest and upper ridging covering the majority of the
CONUS east of the Rockies. A belt of enhanced mid-level flow
persists between these two features, arcing anticyclonically from
southern CA through the central Rockies and northern Plains into the
Upper Midwest/Upper Great Lakes and eventually through the
Northeast. Recent surface analysis shows a reservoir of low-level
moisture beneath the upper ridging, to the south and east of this
belt of stronger mid-level flow. Much of this area is void of
notable surface features, but a weak front does extend from southern
New England through southern NY, central Lower MI, and central WI to
a weak low over southern MN. A large cluster of showers and
thunderstorms to the south of this front from southern WI into
southern Lower MI. This cluster, which was initiated by warm-air
advection across MN and WI is forecast to continue southeastward
today, likely encountering a diurnally destabilized airmass.

The steeper mid-level lapse rates will remain displaced west of this
region, but ample low-level moisture (i.e. upper 60s/low 70s
dewpoints) coupled with afternoon temperatures from the mid 80s to
mid 90s will still support moderate to strong buoyancy. As such, reintensification and/or new development is anticipated as the
ongoing cluster continues southeastward. Much of this region will be
on the southern fringe of the stronger deep-layer shear, with bowing
line segments as the predominant storm mode. The best overlap
between buoyancy and shear is expected across central and eastern
OH, where a corridor of greater potential for damaging gusts exists.

The threat for damaging gusts will extend into the Mid-Atlantic this
afternoon and evening amid a very warm and moist airmass. Vertical
shear will be weak, but ample moisture (i.e. PW values from 1.8" to
2"), strong buoyancy, and steep low-level lapse rates will support
the potential for strong outflow capable of wind damage. Bowing line
segments will be the primary storm mode here as well.

...Central Plains...
Weak lee troughing could contribute to modest low-level convergence
from western KS across western/central NE into southwest SD.
Dewpoints will likely be in the low to mid 60s within this
convergence zone, and steep mid-level lapse rates will contribute to moderate/strong buoyancy. Even so, warm mid-levels may prevent the
airmass from completely destabilizing. The remaining convective
inhibition, coupled with the presence of large-scale height rises
across the region, casts doubt to whether successful convective
initiation will occur. Any mature updrafts could result in strong
downdraft, but uncertainty is too high to introduce any
probabilities with this outlook.

..Mosier/Lyons.. 09/04/2026

$$
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ACUS01 KWNS 050524
SWODY1
SPC AC 050522

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1222 AM CDT Sat Sep 05 2026

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE OHIO VALLEY INTO THE SOUTHERN MID-ATLANTIC AND CAROLINAS...

...SUMMARY...
Severe thunderstorms capable of mainly damaging gusts are possible
across portions of the Ohio Valley into southern Mid-Atlantic and
Carolinas on Saturday afternoon and evening. Isolated occurrences of
large hail and severe wind gusts also appear possible over parts of
the northern and central Plains Saturday into Saturday night.

...Synopsis...

A prominent mid-level ridge will persist over the central CONUS
between upper lows over the Pacific Northwest and the Gulf of St.
Lawrence into NB/NS. Several weak disturbances (some of convective
origin) will progress through the periphery of the ridge, serving as
foci for thunderstorm development. At the surface, an area of low
pressure is forecast over the western Dakotas with an associated
boundary --the location of which may be modified by convective
outflow-- extending into the OH Valley and southern Mid-Atlantic.
The eastern extension of the boundary will begin to push south as a
cold front Saturday afternoon into night as high pressure builds
into the Great Lakes.


...Ohio Valley into the Carolinas...

A mature to decaying MCS is expected to be ongoing 12Z Saturday over
portions of the middle to upper OH Valley, aided by a subtle
mid-level disturbance/possible MCV. There is considerable
variability across the 00Z convection-allowing models in the
longevity and extent of the convective system over the central
Appalachians into southern Mid-Atlantic through the remainder of the
morning. Should the MCS remain intact, isolated occurrences of
damaging wind are possible.

Renewed thunderstorm development is likely by afternoon along the
residual MCS cold pool and/or synoptic front as temperatures in the
90s to around 100 combine with boundary-layer dewpoints in the low
to mid 70s to yield MLCAPE up to 2000-3000+ J/kg with steepening
low-level lapse rates. Additionally, the models indicate some
enhancement of mid-level winds in association with the
disturbance/MCV moving through the southern Mid-Atlantic during the
afternoon, which may yield more organized multicells and line
segments with the predominant hazard being damaging wind gusts into
the evening.

Farther to the west, additional strong to severe storms appear
possible along and ahead of the composite boundary from the vicinity
of the OH River south into the Cumberland Plateau where widely
scattered damaging wind gusts also appear possible.


...Northern and Central Plains...

A band of elevated thunderstorms is expected to be ongoing 12Z
Saturday, centered over eastern SD. That activity is expected to
diminish through the morning with the cessation of the nocturnal
low-level jet; however, isolated occurrences of large hail and
severe wind gusts appear possible prior to dissipation. In the wake
of the early-day storms, the presence of steep low/mid-level lapse
rates and richer boundary-layer moisture with eastward extent will
contribute to a moderately to strongly unstable air mass by
afternoon with MLCAPE of 2000-3500+ J/kg.

Nebulous forcing for ascent and capping relating to the proximity of
the mid-level ridge axis lead to uncertainty in the specific details
regarding the location and extent of surface-based thunderstorm
development during the afternoon into evening. However, the presence
of the surface low, outflow-modified surface front, and a lee trough
over the High Plains will be candidates for storm development. The
strongest deep-layer shear (30-40 kt) is forecast to the north of
the surface low and composite boundary over ND and northern SD into
western MN where a conditional risk of supercells capable of large
hail and severe wind gusts exists. Elsewhere, high-based pulse and
multicell storm modes appear possible with the primary hazard being widely-spaced severe wind gusts.

The isolated severe threat may persist into the overnight hours in
the vicinity of a nocturnally strengthening low-level jet.


...Western Montana...

A belt of enhanced mid/upper-level flow will exist across the
region, to the east of the upper low over the Pacific Northwest.
Heating along the high terrain coupled with the possible influence
of a weak mid-level disturbance is expected to support an increase
in high-based showers and a few thunderstorms during the afternoon
and evening. While lapse rates will be steep with strong deep-layer
shear, the absence of appreciable moisture will limit MLCAPE to
generally less than 250 J/kg. As such the potential for severe wind
gusts is currently too low to warrant 5% wind probabilities.

..Mead/Chalmers.. 09/05/2026

$$
--- MultiMail/DOS
* Origin: capitolcityonline.net * KY, USA (618:250/10)

ACUS01 KWNS 061252
SWODY1
SPC AC 061251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Sun Sep 06 2026

Valid 061300Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE SOUTHERN APPALACHIANS INTO THE SAVANNAH RIVER VALLEY...AND OVER
PARTS OF WESTERN AND CENTRAL MONTANA...

...SUMMARY...
Widely scattered damaging wind gusts are likely across portions of
the Southeast this afternoon and early evening. Widely scattered
large hail occurrences are expected across portions of western and
central Montana this afternoon and evening. Additional areas at risk
for isolated severe wind and hail are parts of the Interior West,
over the northern and central High Plains, and from the eastern
Dakotas and western Minnesota into the Ozark Plateau and Gulf Coast states.

...Southern Appalachians through coastal SC and GA...
A moist airmass is in place across the region this morning, with
recent surface analysis revealing a reservoir of low to mid 70s
dewpoints. Strong heating is anticipated across this region today,
with afternoon temperatures reaching the low to mid 90s. This strong
heating will destabilize the airmass and contribute to
moderate/strong buoyancy, with MLCAPE around 2000-2500 J/kg likely
during the late afternoon. A subtle shortwave trough will progress
through the northwesterly flow aloft extending over the area,
interacting with this destabilized airmass to support thunderstorm
development. Vertical shear will generally be weak, limiting updraft organization and promoting a predominantly outflow-dominant storm
mode. Even so, steep low-level lapse rates and abundant moisture
will promote the potential for damaging wind gusts with any
longer-lived multi-cells or line segments. Updraft augmentation due
to storm interactions could also result in isolated hail.

...Ozark Plateau into the Gulf Coast States...
A corridor of greater low-level moisture arcs from the Southeast
states through Arkansas and Missouri. Daytime heating will
destabilize this airmass, helping to support thunderstorm
development in areas of low-level confluence. Weak forcing for
ascent and vertical shear are expected to limit storm organization.
However, the degree of instability will support briefly intense
pulse-type storms capable of locally damaging wet microbursts during
the afternoon and early evening hours.

...Eastern Dakotas and western Minnesota into the lower Missouri Valley...
A linear MCS continues to push eastward across the central Plains
this morning. A notable vorticity maximum has developed within the
northern portion of this line. Its motion appears to be more
northeasterly than the line itself, and new development is occurring
downstream of this vorticity maximum across south-central/southeast
SD and adjacent northeast NE. A corridor of relatively greater
low-level moisture (i.e. dewpoints in the low 70s) exists downstream
of this vorticity maximum and attendant MCS from eastern SD through
western IA and into northern MO. General expectation is for
thunderstorm coverage and intensity to increase later this
morning/early afternoon as the vorticity maximum/remnant MCS
interact with this moist and diurnally destabilizing airmass. Much
of this development is expected to occur along or to the immediate
cool side of the surface boundary that extends through portions of
the middle and lower MO Valley. Occasionally strong updrafts could
result in isolated hail and/or damaging gusts, but the weak
mid-level flow and associated modest deep-layer shear should limit
storm organization and contribute to clustered multicellular mode.

...Northern Plains into the northern/central High Plains...
Modest height falls may begin to impinge on northern/central High
Plains during the early evening as a low-amplitude shortwave trough
moves a belt of stronger southwesterlies just west of the region.
This modest ascent will augment low-level convergence along the lee
trough to support isolated to widely scattered thunderstorm
development where the lingering convective inhibition can be
overcome. This appears most likely across southeast WY and northeast
CO where persistent low-level easterly flow could keep dewpoints in
the 60s. High-based, outflow-dominant storms will support the
potential for isolated strong to severe gusts.

Increasing mid-level flow will support stronger deep-layer vertical
shear farther north (into eastern MT and western ND), but stronger
convective inhibition may linger, casting doubt whether storms will
initiate. If initiation is realized, storm motion could take it into
the more moist and buoyant airmass north of the surface low where
thermodynamic profiles are favorable for large to very large hail.
Will maintain 5% wind/hail probabilities but introduce a CIG1 for
hail given the conditional potential.

...Northern Great Basin into the northern Rockies...
Increasing height falls and strengthening mid/upper-level flow will
spread across the region today ahead of a vigorous shortwave trough
pivoting through the base of a Pacific Northwest upper low.
Thunderstorm development is anticipated over the higher terrain
before then progressing northeastward towards lower elevations.
Deep-layer vertical shear of 40 to 50 kt will support supercells,
with large hail as the primary severe risk. Greater buoyancy is
expected across central MT, but low-level stability will likely
persist across this region as well, potentially limiting the
severe-wind and tornado potential.

Weaker instability is forecast from northeast NV and northern UT
into central and eastern ID. However, the presence of steep lapse
rates and kinematics mentioned above may yield a few severe storms
capable of severe wind gusts.

..Mosier/Lyons.. 09/06/2026

$$
--- MultiMail/DOS
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ACUS01 KWNS 062002
SWODY1
SPC AC 062000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Sep 06 2026

Valid 062000Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHEAST...MONTANA...AND THE MISSOURI VALLEY...

...SUMMARY...
Scattered damaging winds should occur across parts of the Southeast
this afternoon/early evening. Scattered large hail is forecast
across portions of Montana this afternoon and evening. A focused
corridor for damaging winds and severe hail is forecast across parts
of the Middle and Lower Missouri Valley. Isolated strong to severe thunderstorms may also occur today across parts of the northern
Great Basin, northern/central Plains, and the Ozarks.

...20Z Update...
A Slight Risk was added across parts of the Middle and Lower
Missouri Valley -- driven by 15-percent wind and hail probabilities.
Here, ample diurnal heating amid a very moist air mass is yielding a
corridor of strong surface-based buoyancy (around 4000 J/kg MLCAPE
per the latest HRRR SFCOA data). Large-scale ascent preceding a
convectively augmented midlevel impulse should promote an increase
in storm coverage in this north/south corridor through the
afternoon. The strong buoyancy and around 30 kt of effective shear
should promote a mix of organized clusters and possibly some
supercell structures -- capable of producing damaging wind gusts and
severe hail. See MCD #2253 for more details.

Farther north, the Slight Risk in ND was removed. The latest mode
evolution suggests a reduced hail threat compared to this morning.
However, a locally favorable corridor for damaging wind gusts may
develop into parts of eastern ND this afternoon/early evening.

Elsewhere, the previous forecast remains on track.

..Weinman.. 09/06/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Sep 06 2026/

...Southeast/Lower Mississippi Valley...
Recent visible satellite imagery shows mostly clear skies across
GA/SC late this morning, with surface temperatures already in the
mid/upper 80s to low 90s. A weak front is draped from northwest to
southeast from the southern Appalachians to the Atlantic Coast, with
generally low to mid 70s surface dewpoints present to its south.
Continued diurnal heating of this moist airmass will support the
development of moderate to strong instability (greater with
southward/westward extent into GA/AL and north FL). Compared to the
past couple of days, this region will be displaced from the stronger
mid-level west-northwesterly flow present across the
Mid-Atlantic/Northeast. Corresponding deep-layer shear is expected
to remain rather modest (less than 25 kt), with only loosely
organized updrafts forecast. Even with these kinematic limitations,
steepening low-level lapse rates through the afternoon may still
promote isolated to scattered damaging winds with clusters that
develop and spread south-southeastward through the early evening.
Isolated hail may also occur with the more robust cells that can
develop initially. The damaging wind threat should be more isolated
with westward extent into the lower MS Valley compared to GA and the
Carolinas, where the Slight Risk has been maintained with some expansion.

...Northern Great Basin into the Northern Rockies/High Plains...
A closed mid/upper-level low over the Pacific Northwest and British
Columbia will pivot towards the northern Rockies through the period,
with a belt of enhanced mid-level flow overspreading the northern
Great Basin into the northern Rockies and adjacent High Plains in
MT. At the surface, mostly cloudy conditions are present over much
of western/central MT this morning. Even so, recent NAM/RAP forecast
soundings across this region show supercell profiles later this
afternoon and evening as mid/upper-level winds foster strong
deep-layer shear. Current expectations are for multiple supercells
to develop initially over the higher terrain and spread quickly
northeastward. While there is still some uncertainty regarding
boundary-layer destabilization, sufficient MUCAPE is forecast to
support supercell maintenance into the adjacent High Plains through
the evening. Large hail should be the main threat with this activity
(with some 2+ inches possible given the very favorable deep-layer
shear), but isolated severe gusts may also occur. The Slight Risk
has been adjusted/expanded a little eastward in MT based on latest
short-term guidance trends. High-based thunderstorms may also pose
an isolated threat for severe gusts across parts of the northern
Great Basin this afternoon.

...Northern/Central Plains into the Upper Midwest/Missouri Valley and Ozarks... Ongoing and likely elevated supercells with a threat for large hail
across parts of western ND are being aided by a subtle mid-level
shortwave trough cresting the upper ridge that is anchored over the
central CONUS. Favorable lapse rates aloft and modestly enhanced mid/upper-level southwesterly flow is likely supporting updraft organization/intensity with this ongoing activity. The airmass
downstream across central/eastern ND should gradually destabilize
through the afternoon, with a moist low-level airmass present to the
east of a weak surface low over eastern MT/southwest ND/northwest
SD. It remains unclear whether these ongoing supercells will be
maintained farther east across ND, but given the favorable airmass
and sufficient deep-layer shear present, have opted to add a
targeted Slight Risk for the large hail potential.

Additional convection is occurring farther south in SD, southwest
MN/northwest IA, and northeast NE in association with a mid-level
vorticity maximum evident on water vapor satellite imagery moving
eastward across SD/NE. There is a narrow corridor of greater
instability present across this region southward to the Ozarks,
generally along/near a weak surface front. Isolated hail may occur
with the stronger cores in the short term, but it remains unclear if
convection will be able to form into a southward-moving cluster
across eastern NE/western IA later this afternoon and evening. If
this does occur, then a greater threat for severe/damaging winds
would exist. Have deferred a possible upgrade to Slight Risk given
the uncertainty with how ongoing convection will evolve/impact the
developing warm sector, and due to the presence of the large-scale mid/upper-level ridge and generally modest flow aloft. A separate
area of high-based thunderstorms that should develop this afternoon
along/east of a surface lee trough across the central High Plains
could produce occasional hail and severe gusts, even as deep-layer
shear remains modest.

$$
--- MultiMail/DOS
* Origin: capitolcityonline.net * KY, USA (618:250/10)

ACUS01 KWNS 071613
SWODY1
SPC AC 071612

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1112 AM CDT Mon Sep 07 2026

Valid 071630Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PARTS OF CENTRAL NORTH DAKOTA AND SOUTHEAST SOUTH DAKOTA...

...SUMMARY...
Widely scattered severe storms capable of mainly large hail are
expected over portions of North Dakota as well as southeast South
Dakota into northeast Nebraska this afternoon into evening. Isolated
damaging wind potential will exist over the northern and central
Plains into upper Mississippi Valley. Locally damaging wind gusts
appear possible this afternoon over the central Gulf Coast states.

...ND...
A fast-moving shortwave trough currently over WY/MT will track
northeastward into the Dakotas this afternoon. Strong
heating/mixing in southwest ND will lead to a sharpening dryline
across central ND by mid/late afternoon. This will be the likely
focus for thunderstorm development after 22z. Forecast soundings in
the warm-sector east of the dryline suggest sufficient low-level and
deep-layer shear for supercell storm-modes. Large hail and perhaps a
tornado or two are possible in the most intense storms. This
activity will spread eastward into northeast ND this evening before
weakening.

...CO/KS/NE/SD...
A weak surface boundary is present today from northeast CO into
central NE. Scattered afternoon thunderstorms will form over the
mountains of central CO, with development spreading eastward along
the boundary through the afternoon. Strong heating and a deeply
mixed boundary-layer will promote intense downdrafts in the
strongest cores. By early evening, activity may spread into
southeast SD where greater low-level moisture and CAPE will pose a
risk of a few more intense storms capable of hail or even a tornado.
Recent model solutions have been backing off on this SD scenario,
but will maintain the ongoing SLGT for now.

...LA/MS/AL...
Hot and humid conditions will prevail over the central Gulf coast
region today, with full sunshine and dewpoints in the low-mid 70s.
Steering flow is weak, but high CAPE and ample moisture suggest a
risk of occasional intense downdrafts in the strongest storms.

..Hart/Thornton.. 09/07/2026

$$
--- MultiMail/DOS
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ACUS01 KWNS 081233
SWODY1
SPC AC 081231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Tue Sep 08 2026

Valid 081300Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
CENTRAL IOWA AND FAR EASTERN NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly severe wind gusts
appear possible across portions of Iowa and eastern Nebraska Tuesday
afternoon and evening. More sporadic occurrences of severe winds and
large hail may occur from portions of the upper Midwest into the
central Plains.

...Central Plains into the upper Midwest...
An extensive low-level jet is currently in place from the southern
High Plains through the Upper Midwest. Warm-air advection associated
with this feature is contributing to showers and thunderstorms from
eastern NE through WI and into western Upper MI. This activity is
forecast to gradually shift northeastward this morning while the
embedded storms also gradually diminish in strength. These showers
and thunderstorms, and associated warm low to mid-level
temperatures, are expected to limit destabilization across much of
WI and Upper MI.

Some moderate buoyancy is possible by the early afternoon across MN,
just ahead of a cold front pushing eastward into the region.
Lingering convective inhibition will likely limit convective
initiation, and considerable uncertainty exists regarding
thunderstorm coverage. This uncertainty precludes introducing any
severe probabilities, but the combination of moderate buoyancy and
strong deep-layer shear over the region would support some severe
potential with any updrafts that persist and mature.

Farther south and west (i.e. from IA through eastern/southern NE
into northern KS), stronger daytime heating will contribute to a
well-mixed boundary layer, characterized by steep low-level lapse
rates and dewpoints in the 60s to low/mid 70s F. This air mass is
expected to become moderately to strongly unstable by late afternoon
with MLCAPE of 2000-3000 J/kg. Thunderstorm development is expected
as the southeastward-progressing cold front interacts with this
destabilized and buoyant airmass. The stronger vertical shear will
be displaced north/northeast of the greater buoyancy, but 30 to 35
kt of effective bulk shear is still sufficient for some storm
organization. A largely parallel shear-vector orientation with the
front suggests that initial storms should grow upscale quickly into
line segments or broken bands, with some tendency for undercutting
as well. Even so, a few damaging wind gusts will be possible from
mid afternoon through evening. The low-level jet will increase again
from western KS through central IA this evening resulting in a
corridor of stronger low-level shear. This low-level shear will
support a low-probability tornado risk, but a more robust threat is
expected to be limited by largely outflow-dominant and/or elevated storms.

...CO Plains into western KS...
Thunderstorm development appears likely across the higher terrain of
central CO as the mid-level flow veers more westerly during the late
afternoon. Moist post-frontal northerly low-level flow is expected
across the CO Plains and western KS this evening, which could result
in enough buoyancy to maintain modest intensity as the central CO
storms progress eastward. High-based storm character and prevailing
steep low-level lapse rates may result in a few stronger gusts as
this cluster moves eastward into western KS.

..Mosier/Lyons.. 09/08/2026

$$
--- MultiMail/DOS
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ACUS01 KWNS 091243
SWODY1
SPC AC 091241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Wed Sep 09 2026

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL OHIO
FROM WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today. A more organized
severe weather threat is expected from eastern Ohio to western New York.

...Synopsis...
Early-morning satellite imagery show broad upper troughing from the
Pacific Northwest/British Columbia through the Upper Great Lakes and
Ontario. Several shortwave troughs are embedded within this larger
upper troughing, including one moving into northern MN and another
farther north across far northwestern Ontario. A belt of moderate to
strong mid-level westerly/southwesterly flow extends between the
base of these two waves. Expectation is the southern wave to move
quickly eastward through the Upper Great Lakes and Ontario,
accompanied by mid-level jet max.

Surface analysis places a occluded low over far northwestern
Ontario, with a cold front extending southward into western Upper MI
and then back southwestward through central NE. An outflow-augmented pre-frontal trough precedes this front, extending from a low in
southwest Lower MI to another low over northeast KS to another over
far southwest KS/far southeast CO. Both the cold front and
pre-frontal trough are expected to progress modestly
southward/southeastward today. Two corridors of relatively higher
thunderstorm coverage are anticipated this afternoon/evening, one
from eastern OH into western PA/western NY and the other farther
southwest from the Lower MO Valley into the TX/OK Panhandles.

...Central Ohio into western New York...
Moist low-levels are already in place from the OH Valley into
western PA and NY, with recent surface analysis sampling upper 60s
dewpoints in central OH decreasing to the low/mid 60s across western
PA and western NY. This moist airmass is expected to destabilize
amid modest low-level moisture advection and filtered insolation,
ahead of a convectively augmented vorticity maximum. With the cold
front still well to the northwest, this vorticity maximum will be
the primary impetus for thunderstorm development, augmenting the
weak low-level confluence along the weak pre-frontal trough. A
predominately linear/clustered storm mode is anticipated, but
strengthening mid-level flow will support effective bulk shear from
30 to 40 kt, which could support some more persist/organized line
segments. Damaging gusts are the primary risk with any of these more
organized segments. Low-level hodographs do show some notable
curative, particularly from western PA into western NY after 00Z,
amid a strengthening low-level jet. As such, there is a
low-probability tornado risk is these areas.

...Lower OH and MO Valleys into the TX/OK Panhandles...
Thunderstorm coverage is gradually expected to increase across the
region this afternoon and evening, beginning near a surface low move
across the Lower MO Valley before expanding back southwestward along
the southward-progressing front. The stronger vertical shear will be
displace north of the front, and a largely disorganized,
outflow-dominant storm mode is anticipated. Slightly better flow
aloft may favor a more focused cluster across the Mid-Mississippi
Valley into western Kentucky/Tennessee. Steep low-level lapse rates
and high cloud bases could support strong gusts from the Lower MO
Valley into the TX/OK Panhandles.

...Southern AZ...
Afternoon thunderstorms are expected over the higher terrain near
the southern AZ/NM border. There is some potential this activity
progresses westward into the lower elevations of southern AZ.
However, upper ridging will be centered over this region and
vertical shear will be weak, resulting in slow storm motion and
disorganized, outflow-dominant structures. A few strong gusts could
result from any more persistent updrafts.

..Mosier/Lyons.. 09/09/2026

$$
--- MultiMail/DOS
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ACUS01 KWNS 111228
SWODY1
SPC AC 111226

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0726 AM CDT Fri Sep 11 2026

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes should
occur late this afternoon into tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a conditional risk for large hail and
severe gusts will exist late this afternoon into the evening.

...Upper Midwest into the Central Plains...
Primary large-scale upper troughing will remain over central Canada
today, with an embedded mid-level shortwave trough forecast to eject
eastward over the northern Plains into the Upper Midwest through the
period. A modest surface response will occur across SD as the
shortwave trough ejects eastward, with most guidance suggesting a
sub-1000 mb low will develop into eastern SD by 12/00Z. A surface
cold front attendant to this low and the primary surface low over
central Canada will move east-southeastward across parts of the
Upper Midwest into the northern Plains, with a dryline extending
southward across the central Plains. A narrow corridor of 60s
surface dewpoints will be in place ahead of the cold front/dryline,
with diurnal heating aiding moderate destabilization along with
steepened mid-level lapse rates. Most guidance, including recent
NAM/RAP runs, show minimal MLCIN along/ahead of the front in far
northeast SD/western MN by 22-01Z. Convective development appears
likely in this time frame across this region, owing to sufficient
low-level convergence along the front coupled with forcing for
ascent associated with the mid-level shortwave trough.

Various NAM/RAP forecast soundings show strongly veering and
gradually strengthening winds with height through low/midlevels, and
35-45 kt of deep-layer shear will easily support organized
convection. Initial supercells should pose a threat for large hail
(isolated 2+ inches possible), but convective mode will probably
trend towards clustering fairly quickly given the presence of the
cold front and strengthening low-level jet this evening. Any
supercells that can remain at least semi-discrete into the early
evening may also have a tornado threat with greater low-level shear
forecast in this time frame. But, confidence in this scenario
occurring remains fairly low due to the mode transition expected.
Scattered severe/damaging winds should occur with any clusters or
bowing line segments that can develop and spread eastward through
the evening. However, the wind threat will likely wane with eastward
extent across MN into western WI by late this evening given the
narrow zone of destabilization forecast.

Convective initiation and overall thunderstorm coverage from
southeast SD/southwest MN into the central Plains are highly
uncertain and conditional this afternoon/evening, as the better
forcing for ascent with the shortwave trough will likely remain
across western/northern MN along and northeast of the surface low.
Still, a favorable thermodynamic environment and sufficient (25-35
kt) deep-layer shear would conditionally support severe hail/wind
with any thunderstorms that can develop and be sustained. There is
some signal in model guidance for successful convective initiation
across southern NE into northern KS late this afternoon/evening
where hotter surface temperatures are forecast. The southern extent
of the Marginal Risk has been adjusted to account for this
possibility, and the Slight Risk has generally been confined to
where greater confidence exists in robust thunderstorm development
(far northeast SD into western/northern MN).

...Mid-South into the Tennessee Valley/Carolinas and Virginia...
Two weak mid-level perturbations are evident in water vapor
satellite imagery this morning across the Southeast: one over AR,
and the other along the central Gulf Coast. These features will
generally track east-northeastward through the day, and should aid
additional thunderstorm development this afternoon. A stalled
surface front extending from the ArkLaTex into the TN Valley and
northeastward to VA should also provide a focus for thunderstorms.
Current expectations are for generally disorganized/pulse-type
convection to pose a threat for occasional damaging winds as diurnal
heating destabilizes the boundary layer and steepens low-level lapse
rates. But, modestly enhanced mid-level flow across parts of the
Mid-South and VA could promote loosely organized clusters with some
damaging wind threat as well.

..Gleason/Lyons.. 09/11/2026

$$
--- MultiMail/DOS
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