990
ACUS01 KWNS 120456
SWODY1
SPC AC 120455

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1155 PM CDT Tue Jun 11 2024

Valid 121200Z - 131200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NORTHERN MINNESOTA...

...SUMMARY...
Scattered severe thunderstorms capable of very large hail to 3 inch
diameter, damaging wind gusts to 65 mph, and a couple of tornadoes
will be possible across parts of the Upper Midwest today. The
probable time frame for the most intense storms should be centered
on late afternoon to early evening.

...Upper Midwest Vicinity...

A 50-60 kt westerly 500 mb jet will overspread MN and portions of
northern WI today. As this occurs, an EML plume will advect east
into MN and vicinity, with steep midlevel lapse rates to near 8 C/km
forecast. Meanwhile a surface trough/cold front will shift east
across the eastern Dakotas and MN through the period. Ahead of the
surface boundary, southerly low-level flow will aid in low-level
theta-e advection, and surface dewpoints will climb into the 60s F.
This moist boundary-layer beneath steep midlevel lapse rates will
support strong destabilization, and MLCAPE values around 2000-3000
J/kg are expected.

Vertically veering wind profiles, also increasing in speed in the
mid/upper levels, will support supercells. Forecast soundings show
enlarged/looping low-level hodographs becoming elongated/straight
above 3 km. This environment will be very favorable for supercells
capable of producing very large hail. A couple of tornadoes also
will be possible, especially across parts of northern MN where
better organized/more intense supercells are expected and SRH
increases in the 22-00z time frame. Isolated damaging gusts also
will be possible. Confidence has increased sufficiently regarding
coverage/spatial extent of a corridor of greater significant hail
potential, supporting an upgrade to an Enhanced risk (level 3 of 5)
across parts of northern MN.

Severe potential will gradually diminish across northern WI and the
Upper Peninsula where instability will be less and stronger
inhibition is forecast.

Further south across eastern SD/southern MN/northern IA, clusters of
elevated storms may develop early in the day in response strong warm
advection. This activity will initially be elevated, but could still
pose a risk for hail. With time into the afternoon as additional
heating/moistening occurs, this activity could become more
surface-based. If this occurs, damaging gusts in addition to hail
will be possible across southern MN/northern IA.

..Leitman/Weinman.. 06/12/2024

$$