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SPC MD 1487

MD 1487 CONCERNING TORNADO WATCH 385... FOR FAR SOUTHEAST MINNESOTA...NORTHEAST IOWA...MOST OF WISCONSIN
MD 1487 Image


Mesoscale Discussion 1487
NWS Storm Prediction Center Norman OK
0820 PM CDT Thu Sep 20 2018

Areas affected...Far southeast Minnesota...northeast Iowa...most of
Wisconsin

Concerning...Tornado Watch 385...

Valid 210120Z - 210315Z

The severe weather threat for Tornado Watch 385 continues.

SUMMARY...Mainly a damaging wind threat continues with the squall
line from northeast IA to west-central WI. A gradual weakening trend
is expected over the next several hours.

DISCUSSION...A squall line, located from east of EAU to CCY, is
surging eastward into a cooler, more stable airmass. While up to
1500 J/kg MLCAPE is present across the southernmost portions of the
discussion area, buoyancy is expected to wane across the entire area
with the onset of nocturnal cooling and associated stabilization of
the boundary layer. Still, impressive shear profiles remain in place
across the discussion area (50-60 knot effective bulk shear vectors
normal to the squall line and 300+ m2/s2 effective SRH). As such,
while an overall weakening trend is expected with the squall line
over the next several hours, the threat remains for at least a few
more severe wind gusts and possibly a brief QLCS tornado,
particularly with portions of the squall line interacting with the
warm front.

..Squitieri/Grams.. 09/21/2018

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

ATTN...WFO...MQT...GRB...MKX...DVN...DLH...ARX...MPX...DMX...

LAT...LON   42889289 43169312 43939308 44899283 45379245 45689139
            45989093 45988910 45478759 44888725 43948808 42739088
            42639106 42889289 

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