887
ACUS02 KWNS 250526
SWODY2
SPC AC 250524

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 AM CDT Sat Jul 25 2026

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
MISSISSIPPI VALLEY INTO UPPER MIDWEST...

...SUMMARY...
Severe thunderstorms capable of mainly large hail and damaging winds
are possible from the upper Mississippi Valley and Great Lakes into
portions of the mid Missouri Valley on Sunday and Sunday night.

...Synopsis...

A dominant upper high will remain anchored over the central and
southern Plains with an associated ridge extending north into
central Canada. Within the periphery of the ridge, a belt of
enhanced mid-level flow will extend from the Pacific Northwest
through south-central Canada into the Great Lakes and middle OH
Valley. A series of weak mid-level disturbances will translate
through the stream of higher-momentum flow, the most notable of
which is a short-wave trough that will crest the ridge axis over
SK/MB. Modest height falls are expected downstream from that feature
from northern MN into the upper Great Lakes Sunday night/early
Monday.

At the surface, a cool front attending the SK/MB system will advance
through the northern High Plains into the ND-MN Red River Valley. A
weak front will settle south through northern parts of MN and WI
before stalling, while a separate frontal system extends from the
Southeast into the Midwest with another boundary.


...Upper Mississippi Valley and Great Lakes into the Mid Missouri
and Ohio Valleys...
Capping associated with the mid-level ridge and the subtle nature of
mechanisms to sustain forcing for ascent lead to considerable
uncertainty in the location, areal coverage, and intensity of
thunderstorms Sunday into Sunday night. That being said, a few
early-day thunderstorms appear possible across the upper Midwest
within a zone of warm advection and aided by the glancing influence
of a weak disturbance moving through the upper Great Lakes. The
storms would likely be elevated within a plume of moderate
instability and ample vertical shear, suggesting some potential for
large hail and damaging winds.

By afternoon, a reservoir of moderate to strong instability is
forecast across the Midwest with the various models indicating the
potential for diurnally enhanced thunderstorm development at various
locations from the mid MO Valley into lower MI. Confidence in any
one scenario remains low, and as such, a modest expansion of the
level 1/Marginal Risk was made across parts of the OH Valley to
account for the broad range of potential outcomes. Given the degree
of instability and seasonably strong vertical shear, higher severe
weather probabilities and related conditional intensity groups may
become necessary once forecast details become more clear.

As alluded to in the synopsis, stronger forcing for ascent tied to
the approaching Canadian disturbance and surface front may support a
more focused area of thunderstorm development over MN Sunday night.
Subsequent upscale growth into a forward-propagating MCS appears
possible, which would increase the potential for a swath of severe
wind gusts.


...Southeast...
One or multiple weak disturbances aloft are expected to overspread
the region, along with a slight increase in mid/upper-level winds.
In response, a weak surface low may develop across upstate SC, along
a subtle front/confluence zone in the area. Thunderstorms are
expected to increase in coverage and intensity through the afternoon
along the front and developing sea-breeze boundaries within a very
moist and moderately unstable air mass. Steep low-level lapses and
high precipitable water content will enhance downdraft potential
with an associated risk for locally damaging winds.

..Mead.. 07/25/2026

$$