ZCZC SPCSWOMCD ALL
ACUS11 KWNS 290317 
SPC MCD 290317 
WIZ000-MNZ000-290415-

Mesoscale Discussion 1381
NWS Storm Prediction Center Norman OK
1017 PM CDT Wed Jul 28 2021

Areas affected...Western Wisconsin and southeast Minnesota

Concerning...Severe Thunderstorm Watch 399...

Valid 290317Z - 290415Z

The severe weather threat for Severe Thunderstorm Watch 399
continues.

SUMMARY...There is an increasing threat for severe (potentially high
end) damaging winds across portions of western Wisconsin and eastern
Minnesota.

DISCUSSION...Recent KARX and KMPX radar trends show an increasing
area of strong winds in St. Croix county with hints of an increasing
rear inflow jet over the past few scans. Given the very unstable
downstream environment (3500 J/kg MLCAPE) and 40 knots of flow at
1km from the KMPX VWP, the environment is primed for very strong
winds. Therefore, as this cluster moves southeast and matures,
hurricane force winds are likely. The current trajectory of this
cluster would bring the threat into portions of southeast Minnesota
which are not currently in watch 399. Therefore, after collaboration
with the local forecast office in La Crosse, Wisconsin, watch 399
will be expanded into southeastern Minnesota and northeastern Iowa.

..Bentley.. 07/29/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ARX...MPX...

LAT...LON   45239264 45179212 44759158 44129127 43789128 43749147
            43859200 44009249 44389291 45159302 45239264 

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