Jacksonville, FL...Milwaukee, WI...Kansas City, MO...Cleveland, OH...Minneapolis, MN...
Probabilistic Damaging Wind Graphic
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 201937
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0237 PM CDT Sun Jun 20 2021
Valid 202000Z - 211200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EXTREME EASTERN IOWA ACROSS CHICAGOLAND TO NORTHWEST OHIO AND
SOUTHERN LOWER MICHIGAN...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK...AND ALSO OVER PARTS OF GEORGIA AND THE CAROLINAS...
Scattered severe storms are expected across the Midwest into the
lower Great Lakes/upper Ohio Valley. Large hail, severe/damaging
winds, and a few tornadoes are possible. Damaging winds and a couple
of tornadoes are also possible across the Southeast.
Air mass downstream of Tropical Depression Claudette continues to
destabilize amid modest heating and ample low-level moisture. As
mentioned in MCD #1034, a couple of transient supercells may pose an
isolated risk for a tornado or two through the afternoon. The
highest conditional risk for a tornado appears to be over parts of
eastern NC during the afternoon due to the larger hodographs.
Additionally, based on recent trends and the location of center of
TD Claudette, the severe risk across southeast GA has diminished
enough to remove Slight Risk-equivalent probabilities. Isolated
threat across southern GA/northern FL merits continued inclusion of
5% wind probabilities.
Forecast delineated outlined in the previous outlook (discussion
below) remains valid and no changes are needed.
.PREV DISCUSSION... /ISSUED 1122 AM CDT Sun Jun 20 2021/
...MO to OH...
Current water vapor loop shows a convectively augmented vort max
over northern MO. New thunderstorm development has occurred in the
past couple of hours in this region, with a corridor of rapid
heating/destabilization occurring to the east from northeast MO into
northern IL. Storms will likely intensify through the afternoon
along this axis, with the risk of damaging winds, large hail, and
isolated tornadoes. 12z CAM solutions differ on the handling of
this cluster, but the potential appears to exist for a longer-lived
bowing structure that would track all the way into northern OH this
evening. Please refer to MCD #1032 for short-term details.
Latest surface analysis shows a low over west-central MN. clearing
skies ahead of the low, along with southerly low-level winds, will
help to warm/moisten and destabilize this area by mid-afternoon. A
consensus of model guidance shows intense thunderstorm development
later today over southeast MN, southwest WI, and parts of
northern/eastern IA. Large hail and damaging winds will be possible
with these storms. A combination of remnant cloud debris and
outflow boundaries complicate the scenario, but also increase the
conditional risk of supercells and perhaps a few tornadoes this
evening. If the storms over MO do not materialize into a
longer-lived bow, then this area of storms may persist for several
hours and track eastward across the ENH risk area.
The remnants of Claudette continue to affect parts of GA and the
Carolinas today, with relatively strong low-level winds from
southeast GA into southern SC. Considerable daytime heating and
ample low level moisture will provide favorable thermodynamics for a
few intense afternoon thunderstorms capable of damaging wind gusts
and a few tornadoes.
...Southeast CO into southern KS late tonight...
A surface cold front will extend from eastern CO into southern KS
tonight, providing the focus for a few evening/overnight
thunderstorms. Sufficient CAPE/shear along this zone will pose a
risk of hail in the strongest storms.
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