481
ACUS01 KWNS 260559
SWODY1
SPC AC 260558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Sat Jul 26 2025

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Severe thunderstorms accompanied by damaging wind gusts will be
possible Saturday afternoon and evening in parts of the northern
Plains. Isolated strong to severe storms will be possible from the
Ohio Valley and lower Great Lakes into the mid-Atlantic region, and
across the central High Plains and much of Montana.

...Synopsis...
An expansive upper-level cyclone over the southeast U.S. will move
little on Saturday, as a broad upper-level trough persists along the
West Coast. A modest belt of stronger mid-level westerlies will
extend across the northern CONUS. A quasi-stationary surface front
will extend east-west across the northern Ohio Valley and southeast
across the mid-Atlantic.

...MT east across the northern/central Plains...
Embedded impulses within the western U.S. upper trough, most notably
now moving northeast across UT, will pivot east across MT and the
northern Plains during the day Saturday. Storms may be in progress
Saturday morning, with additional development along a surface trough
across western SD southward into the central High Plains as
large-scale ascent overspreads the area. Storms over western SD
should evolve upscale over time while moving east/northeast, with an
increasing risk for damaging winds, especially across the Slight
Risk area, where strong instability with eastward extent (MLCAPE
over 3000 J/kg across) will be in place. Deep-layer shear will be
supportive of supercell potential with any semi-discrete storm that
develops, with an attendant risk for large hail.

More isolated storms that develop along the surface trough across
western NE/northeast CO will also have the potential for
strong/severe gusts within a very deep/well-mixed boundary layer.

Isolated stronger storms will also be possible across MT, where weak
instability and steep low-level lapse rates will promote some
potential for strong/severe gusts.

...Ohio Valley/Mid-Atlantic Region...
A moist air mass (low-mid 70s surface dew points) will remain in
place south of the quasi-stationary front during the day. Morning
storms will likely be ongoing at 12z Saturday over northern portions
of MO/IL/IN, with some diurnal uptick in coverage/intensity during
the afternoon as a convectively augmented mid-level impulse moves
east across this area. Twenty to 30 kts of deep-layer shear will
result in organized updrafts with a risk for isolated strong wind
gusts and perhaps hail during the afternoon. Isolated storms will
also be possible across the mid-Atlantic, where moderate/strong
mixed-layer instability and modest west-northwest mid-level flow
will support the potential for strong gusts.

..Bunting/Squitieri.. 07/26/2025

$$