Subj : DAY1SVR: Day 1 Convective Outlook
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Aug 12 2025 16:30:31

ACUS01 KWNS 121630
SWODY1
SPC AC 121628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Tue Aug 12 2025

Valid 121630Z - 131200Z

....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE GREAT LAKES AND SOUTHEAST ARIZONA INTO SOUTHWEST NEW MEXICO...

....SUMMARY...
Strong to locally severe thunderstorms are possible over parts of
the Great Lakes/Midwest this afternoon with both damaging winds and
hail possible.  Gusty winds may also occur over southeast Arizona
and southwest New Mexico.

....Great Lakes/Midwest...
Midday satellite/radar composite show a weakened thunderstorm band
moving east-northeast across the eastern part of Lower MI.  Surface
analysis indicates rain-cooled air north of a gust front/outflow
that has become draped from southeast Lower MI into the Michiana
region.  Heating south of this boundary has resulted in temperatures
warming through the mid-upper 80s with dewpoints in the lower 70s.
Additional storms will probably develop along the trailing outflow
and gradually move east-northeast with the mean wind.  Considerably
weaker deep-layer shear is present across the eastern part of the
Corn Belt into the Lower MI vicinity compared to farther north over
the U.P. of MI in closer proximity to a shortwave trough.
Nonetheless, scattered thunderstorms will gradually develop within a
moist/destabilizing airmass and pose a risk for isolated strong to
perhaps locally severe/damaging gusts this afternoon.

Farther north in WI into the U.P. of MI, a weak cold front will move
into the region later this afternoon.  Model guidance shows widely
scattered storms developing as filtered sunshine leads to a
destabilizing boundary layer.  A few stronger thunderstorms are
possible and could yield a localized risk for marginally severe hail
and damaging gusts during the mid afternoon to early evening period.

....Southeast AZ/southwest NM...
Strong heating should result in widely scattered thunderstorms
developing near terrain-favored areas.  Weak shear will result in
disorganized storms, but the development of very steep surface to
500-mb lapse rates will promote strong evaporative cooling with the
more intense downdrafts.  Isolated severe gusts are possible.

...Smith/Squitieri.. 08/12/2025

$$

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