ACUS02 KWNS 250602
SWODY2
SPC AC 250600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Jul 25 2025

Valid 261200Z - 271200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
UPPER MIDWEST...LOWER GREAT LAKES...NORTHERN ROCKIES...CENTRAL HIGH
PLAINS...NORTHERN PLAINS...

...SUMMARY...
Strong to severe thunderstorms accompanied by potentially damaging
wind gusts are possible Saturday afternoon/evening in parts of the
Upper Midwest/Lower Great Lakes. Isolated to widely scattered severe
storms may also occur from the Northern Rockies, central High
Plains, and northern Plains.

...Dakotas...
A belt of stronger mid-level flow will exist near the Canadian
border and should extend into parts of North Dakota. A modest
surface trough/low will likely be situated in parts of the western
Dakotas with a very moist airmass (mid/upper 60s F dewpoints) to the
east of this feature. 3000-4000 J/kg of MLCAPE appear probable along
with 35-45 kts of effective shear. Beneath the upper ridge, forcing
for ascent will not be strong. Capping may be enough to hinder storm
development--a scenario suggested by the ECMWF. However, there does
appear to be a weak perturbation emanating from the central Rockies
that could promote storm development near the surface trough/low, as
suggested by the NAM/GFS. Should this occur, organized supercells
would be possible early in the convective cycle. Large hail and
severe gusts would be the expected hazards. Large
temperature-dewpoint spreads at the surface and weak low-level shear
would likely promote outflow dominance and potential for upscale
growth. This would mean a transition to a broader threat of severe winds.

...Upper Midwest/Lower Great Lakes...
A convectively induced MCV is expected to be moving into northern
Illinois/southern Wisconsin early Saturday morning. This activity is
generally expected to be sub-severe given limited buoyancy. Ahead of
this feature, as well as along the outflow boundary this activity
leaves behind, strong heating of a moist airmass will support MLCAPE
in excess of 3000 J/kg in parts of central Illinois. Farther east,
MLCAPE may be near 2000-2500 J/kg. Shear will generally be weak away
from the MCV/surface boundary, but 30-35 kts of effective shear
along the boundary appears possible. Marginally organized storms
will have some potential to produce damaging downburst winds. The
main uncertainties are the track of the MCV and where the outflow
will be during the afternoon. The general trend in guidance has been
for the more favorable environment to be farther south and
probabilities have been adjusted to reflect this.

...Central High Plains...
Strong heating near the surface trough and aid from a shortwave
trough moving through the Four Corners should allow isolated storm
development by late afternoon. A modest increase in shear across the
surface trough/terrain will also occur. With large
temperature-dewpoint spreads at the surface, isolated severe winds
would be possible. A cluster or two could evolve out of this
activity, but where this will occur is uncertain.

...Northern Rockies...
Stronger mid-level flow will exist across this region.
Moisture/buoyancy will be limited, especially with westward extent.
However, widely scattered to scattered convection will likely
develop within the terrain and move northeastward. How far northeast
the strongest activity progresses is not clear given capping in
parts of central/eastern Montana. However, strong to marginally
severe gusts appear possible with this activity given the deeply
mixed boundary layer.

..Wendt.. 07/25/2025

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