Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 240552
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1252 AM CDT Thu Sep 24 2020
Valid 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHEAST AND UPPER MIDWEST...
...SUMMARY...
Isolated strong to severe thunderstorms may occur Friday across
parts of the Southeast and Upper Midwest.
...Southeast...
Showers and thunderstorms may be ongoing Friday morning across parts
of the Southeast in association with a weak mid-level shortwave
trough. As this trough moves eastward through the day, 30-40 kt of
southwesterly mid-level flow should remain over parts of GA into the
Carolinas. Modest diurnal heating of a moist low-level airmass is
forecast across this area, which should support 500-1500 J/kg of
MLCAPE by Friday afternoon. Around 30-35 kt of effective bulk shear
will likely foster some storm organization as additional convection
develops through the day, with a mix of multicell and marginal
supercell structures possible. Isolated strong/gusty downdraft winds
capable of producing occasional damage appear to be the main threat
through Friday evening, although a tornado or two cannot be ruled
out from parts of eastern GA into the Carolinas where low-level
shear is forecast to be slightly stronger.
...Upper Midwest...
A strong westerly mid/upper-level jet is forecast to persist on
Friday across much of the Pacific Northwest to the northern Rockies
and north-central states. A shortwave trough embedded within this
flow regime will move eastward across the Upper Midwest through the
period. At the surface, a cold front will likewise sweep eastward
across this region, with a modest increase in low-level moisture
occurring ahead of the front across parts of eastern MN into western
WI and vicinity. Most guidance continues to suggest that warm
mid-level temperatures preceding the shortwave trough will keep the
warm sector capped through much of the day. However, it appears
possible that mainly elevated storms may form by Friday evening
along or just ahead of the front across parts of east-central MN
into northwestern WI. Strong deep-layer shear of 40-50+ kt would
foster storm organization, including some supercells initially,
given the presence of 500-1500 J/kg of MUCAPE. Isolated large hail
and perhaps some strong/gusty winds would be possible as storms
spread east-southeastward through the evening.
..Gleason.. 09/24/2020
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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