496
ACUS01 KWNS 121204
SWODY1
SPC AC 121202

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0702 AM CDT Wed Jun 12 2024

Valid 121300Z - 131200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PORTIONS OF NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN...

...SUMMARY...
Scattered severe thunderstorms capable of very large hail, damaging
wind gusts, and a few tornadoes will be possible across parts of the
Upper Midwest late afternoon and early evening.

...Southern MN/WI early today...
Morning water vapor imagery shows a fast-moving shortwave trough
over the western Dakotas.  Lift and enhanced low-level
thermal/moisture advection ahead of the trough has resulted in
scattered thunderstorm development over western MN and eastern SD.
These storms may persist through the morning, tracking across
central/southern MN by early afternoon with some risk of large hail.
 Daytime heating and increasing low-level moisture will eventually
result in moderate CAPE and a risk of organized strong/severe
thunderstorms - mainly from central MN eastward after 18z.  These
storms may grow upscale and track into central WI before weakening,
posing a continued risk of damaging winds and hail.

...Northern MN/WI later today...
In the wake of the aforementioned morning convection, strong daytime
heating and moisture advection will result in a corridor of moderate
CAPE across central/northeast MN by mid/late afternoon.
Temperatures west of this area will heating to near 90F, with
forecast soundings showing little cap, very steep mid-level lapse
rates, and MLCAPE values around 3000 J/kg.  Large scale forcing will
be subtle, leading to the development of discrete supercells.
Several overnight CAM runs suggest intense storms that form will
track into the Arrowhead region of MN and areas around Duluth by
early evening, posing a risk of very large hail, damaging winds, and
a few tornadoes.  Forecast soundings show substantial low-level
shear with effective SRH values of 300+ m2/s2.  It is uncertain how
the early storms over southern MN will affect moisture return.  If
high dewpoint air can make it into the ENH risk area, higher tornado
probabilities may become warranted.  These storms will likely
congeal and spread eastward across northern WI during the evening
with a continued risk of damaging winds and some hail.

..Hart/Bentley.. 06/12/2024

$$