Subj : DAY1SVR: Day 1 Convective
To   : All
From : Mike Powell
Date : Sun Aug 17 2025 10:11:07

ACUS01 KWNS 171221
SWODY1
SPC AC 171220

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0720 AM CDT Sun Aug 17 2025

Valid 171300Z - 181200Z

....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN
NEW ENGLAND....

....SUMMARY...
One or two clusters of thunderstorms may develop and gradually pose
a risk for damaging wind gusts from the northern High Plains into
the Midwest this afternoon and tonight.  Damaging thunderstorm wind
gusts may also occur across parts of the northern Mid Atlantic into
southern New England late this afternoon and evening.

....Northern Plains into Upper Midwest...
A broad upper ridge remains in place over southern/central U.S
today.  Several weak perturbations will top the ridge during this
forecast period, affecting much of the northern Plains and upper
Midwest.  Each of these smaller-scale shortwave troughs will
potentially be associated with a cluster of thunderstorms.
Sufficient low-level moisture and 25-35 knots of westerly flow aloft
pose some conditional risk of severe storms throughout this region,
but considerable uncertainty on the timing and placement of
convection precludes upgrading any areas to SLGT at this time.
Multiple areas of ongoing convection this morning further complicate
the forecast.  Perhaps by 1630z, areas of stronger daytime
heating/destabilization will allow better focus of the severe
outlook.

....Mid Atlantic into southern New England...
A cold front currently extends from OH northeastward into the St.
Lawrence Valley.  Forecast soundings ahead of the front show weak
mid-level lapse rates and limited mid-level dry air.  However,
strong heating into the 80s and 90s F, coupled with dewpoints near
70F will yield MLCAPE around 1000 J/kg.  Sufficient westerly flow
aloft and frontal forcing may be sufficient for isolated strong
storms capable of locally gusty/damaging winds this afternoon.

...Hart/Dean.. 08/17/2025

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