769
ACUS02 KWNS 121727
SWODY2
SPC AC 121726

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 PM CDT Fri Jul 12 2024

Valid 131200Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS...

...SUMMARY...
Multiple clusters of strong to severe thunderstorms are possible
across portions of the Northern Plains into the Upper Mississippi
Valley on Saturday, with the greatest likelihood from Minnesota into
Wisconsin.

...Synopsis...
On Saturday, a strong upper high will remain centered over the Four
Corners states, with a broad, low-amplitude upper trough across much
of southern Canada. In between, a belt of moderate mid to high level
winds will exist, stretching from the northern Rockies
east/southeastward into the upper Great Lakes.

At the surface, a trough will develop roughly from northern MN into
central SD and NE, with a weak front pushing south across ND. A
moist and unstable air mass will exist near and east of the surface
trough in particular, as southwest low-level flow persists.

Elsewhere, a compact shortwave trough will move across New England,
supporting isolated thunderstorms. However, overall lift and
instability with this system do not appear to support severe storms.

...Northern Plains to the upper MS Valley...
Multiple zones of severe storms are expected on Saturday, stretching
from the northern High Plains toward Lake Michigan.

Early-day storms appear likely over parts of northern MN into WI,
possibly in MCS format with attendant strong to locally severe gust
threat. While these systems typically weaken through midday, some
rejuvenation may occur into WI or northern IL as the air mass
destabilizes into the diurnal maximum.

Behind this early activity, air mass recovery and generally
southwest surface winds may support renewed development along
western fringes of any existing outflow. Isolated supercells would
be possible, with localized/brief hail as winds aloft will be
marginal. More likely, damaging winds would occur, as CAPE will be
large.

Later in the day, strong heating near the surface trough will yield
storms over SD and NE, with locally damaging gusts, and perhaps
isolated hail.

Farther west, another concentrated area of storms is forecast,
beginning over northeast MT during the late afternoon, and
persisting overnight into the Dakotas and possibly into western MN
by Sunday morning. Steep lapse rates and 50 kt effective shear
should result in a more favorable supercell environment with hail
risk. With time, an MCS is expected with an increasing damaging wind
threat overnight.

..Jewell.. 07/12/2024

$$