ACUS01 KWNS 261246
SWODY1
SPC AC 261245

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0745 AM CDT Wed Aug 26 2026

Valid 261300Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN GREAT LAKES/MIDWEST...CENTRAL HIGH PLAINS...AND
OZARKS/MID-SOUTH INTO THE LOWER MISSISSIPPI VALLEY...

...SUMMARY...
Isolated to widely scattered severe thunderstorms are forecast today
across parts of the southern Great Lakes into the Midwest,
central/southern High Plains, and the Ozarks into the Mid-South and
Lower Mississippi Valley. Severe/damaging winds should be the main
threat across these regions, though large hail is also possible,
particularly across the central High Plains.

...Southern Great Lakes into the Midwest...
A mid-level shortwave trough over the upper Great Lakes this morning
will progress eastward today across southern Ontario. The basal
portion of this trough will overspread parts of the southern Great
Lakes and Midwest, with a surface cold front moving
east-southeastward across these regions as well. Lapse rates aloft
are forecast to remain rather poor, which may tend to limit updraft
strength to some extent. Still, a corridor of destabilization is
expected along/ahead of the front through the afternoon, with at
least moderate instability likely from eastern IL northeastward into
southern Lower MI. Thunderstorms should develop along/ahead of the
front as convective temperatures are reached by 19-22Z.
Low/mid-level winds will tend to remain fairly modest and veered to
westerly, with up to 25-35 kt of deep-layer shear fostering some
updraft organization.

A mix of multicell clusters and marginal supercells should pose a
threat for both hail and damaging winds, with the wind threat
potentially becoming the primary risk with eastward extent into the
Midwest as thunderstorms grow upscale. A brief embedded tornado may
also occur, but low-level flow is forecast to remain rather veered,
with limited hodograph curvature noted in most NAM/RAP forecast
soundings. The overall severe threat will likely diminish quickly
this evening as convection outpaces the low-level
moisture/instability, and as nocturnal cooling of the boundary layer occurs.

...Ozarks into the Mid-South and Lower Mississippi Valley...
Thunderstorms have developed this morning across southeast MO/far
southern IL, and they should continue to track south-southeastward
into the Mid-South along the MUCAPE gradient noted in latest
mesoanalysis. While sub-severe for now given substantial MLCIN
present, there is some potential for this activity to persist and
eventually strengthen later today across parts of western TN into
northern MS and vicinity as the boundary layer gradually
destabilizes. Have adjusted/expanded wind probabilities a bit
eastward in western TN/northern MS into northern/central AL to
account for this possibility.

Otherwise, additional thunderstorm development is also likely this
afternoon along/near a weak surface front from southern MO into AR
and eastern OK. This activity may be aided by a remnant MCV that
will move eastward across the southern Plains through the day.
Modest deep-layer shear should support some updraft organization,
with multicell clusters likely the dominant mode. High total
precipitable water values and large buoyancy will support robust
downbursts with primarily a scattered damaging wind threat.
Occasional hail may also occur with the strongest cores given the
degree of instability forecast. Some high-resolution guidance
continues to show a southward-moving storm cluster across the lower
MS Valley this evening/tonight. As such, there is potential for at
least isolated damaging winds to persist across parts of southern LA/MS.

...Central/Southern High Plains...
Around 25-35 kt of west-northwesterly mid-level flow will be present
over the southern/central High Plains today, with a mid/upper-level
ridge remaining centered over the Southwest/Four Corners. Modest
low-level upslope flow across the central High Plains should support
convective initiation by early/mid afternoon over the higher terrain
and Front Range. Moderate instability aided by modestly steepened
mid-level lapse rates and sufficient deep-layer shear should all act
to aid updraft organization, with both supercells and clusters
possible. There is still some uncertainty with convective
development farther east across southwest NE this afternoon
along/near a front. But, any thunderstorms that can form and persist
across this area would also pose a severe risk. Both large hail and
severe gusts may occur with convection that spreads
east-southeastward through the afternoon and evening, with some
potential for upscale growth/additional clustering into western KS
this evening.

Farther south across the southern High Plains, mid-level flow and
related deep-layer shear should be somewhat weaker. Still,
convection that develops across central into eastern NM may become
loosely organized while posing an isolated threat for severe gusts
given the presence of a very well-mixed boundary layer. This threat
may continue into parts of the OK/TX Panhandles and west TX through
the evening before eventually weakening.

..Gleason/Broyles.. 08/26/2026

$$
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