ACUS11 KWNS 290201
SWOMCD
SPC MCD 290201=20
WIZ000-MNZ000-290330-

Mesoscale Discussion 1324
NWS Storm Prediction Center Norman OK
0901 PM CDT Wed Jun 28 2023

Areas affected...Extreme east-central MN into northwest WI

Concerning...Severe Thunderstorm Watch 409...

Valid 290201Z - 290330Z

The severe weather threat for Severe Thunderstorm Watch 409
continues.

SUMMARY...Some uptick in storm coverage and intensity remains
possible this evening, with some threat of hail and locally damaging
gusts.

DISCUSSION...Convection has been slow to mature this evening in and
near WW 409, though somewhat more vigorous updrafts with increasing
lightning have been noted along the cold front in extreme
east-central MN/northwest WI. The 00 UTC MPX sounding depicted a
favorable environment for organized convection, with MLCAPE of
around 2500 J/kg and effective shear in excess of 40 kt. However,
the downstream environment is cooler and less unstable, resulting in
a tendency thus far for convection to weaken as it moves eastward
and becomes further removed from the more favorable instability.=20

With time, a warm-advection regime supported by a modest low-level
jet is expected to result in an increase in storm coverage. There
may be a tendency for maturing storms to become slightly elevated,
but increasing moisture above the surface will continue to support
moderate MUCAPE, and a few organized cells/clusters capable of hail
and locally damaging winds remain possible through this evening. A surface-based supercell or two also remains possible in the more
favorable environment across western portions of WW 409, which could
pose a threat for a brief tornado in addition to the hail/wind risk.

Some modest upscale growth is possible with time, which would tend
to propagate south-southeastward along the buoyancy gradient. This
could eventually lead to some severe threat spreading south of WW
409, but the need for any additional watch issuance later tonight
remains very uncertain.

..Dean.. 06/29/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4twUVrzGZytZmyTfZvzJPOH-_rV04a_S_5dwAmsXnYIeDPAdo-lK8srhHPSpaKQ-GBqzSFfO6= awZSSOnYzV3TVvFjn8$ for graphic product...

ATTN...WFO...GRB...DLH...ARX...MPX...

LAT...LON 44859315 46139241 46169114 45979041 45839022 45129010
44749014 44509028 44629180 44769310 44859315=20


=3D =3D =3D
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