474
ACUS03 KWNS 081922
SWODY3
SPC AC 081921

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0221 PM CDT Mon Jun 08 2026

Valid 101200Z - 111200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF EASTERN MINNESOTA...WISCONSIN...EASTERN IOWA...AND NORTHERN
ILLINOIS...

...SUMMARY...
Scattered to numerous severe thunderstorms capable of large to very
large hail, tornadoes, and damaging winds with significant gusts
appear likely across portions of the upper Mississippi Valley and
Midwest Wednesday afternoon into night. More sporadic occurrences of
large hail and damaging winds are possible into the central Plains.

...Synopsis...

An upper low is forecast over southern Alberta/Saskatchewan and
northern MT Wednesday morning. One upper shortwave trough associated
with this system will be oriented over the northern High Plains
Wednesday morning, and will spread eastward through the period into
the Upper Midwest/Great Lakes vicinity. A second upper shortwave
trough will deepen and develop southeast from the northern Rockies
to the central High Plains by Thursday morning.

At the surface, a cold front will initially be located from eastern
ND toward the central High Plains. The northern portion of this
front will develop east across the Upper Midwest, while the
southwestern extension of the front stalls from the Mid-MO Valley
into the southern High Plains as a surface low deepens over NE/KS
overnight.

...Upper MS Valley/Great Lakes toward the Mid/Lower MO Valley
vicinity...

Remnant convection from the Day 2/Tuesday period may be
ongoing/decaying across parts of the region Wednesday morning.
Furthermore, convective outflow could be positioned somewhere across
the Upper Midwest. As a result, evolution of convection from the Day
2 period will likely have some impact on where corridors of greater
severe potential develop on Wednesday. Regardless, rich boundary
layer moisture will spread across parts of MN/WI/IA/IL as a warm
front retreats northward across the Great Lakes and ahead of the
advancing surface cold front. This will foster strong
destabilization across the region as vertical shear increases with
time. Numerous organized severe thunderstorms, possibly both
supercells and bowing segments, are expected with an accompany
all-hazards severe risk, particularly across parts of MN/WI and
possibly IA into northern IL.

With southwest extent into the Mid/Lower MO Valley, effective shear
magnitudes will decrease. However, a very moist and strongly
unstable airmass will be in place ahead of the stalled surface
boundary across KS to western IA. A dryline will also extend into
the southern High Plains, though boundary layer moisture will also
become more modest with southwest extent. Both of these boundaries
will serve as a focus for a second area of severe thunderstorm
potential during the late afternoon/evening, with both large hail
and damaging gusts possible. Additional severe thunderstorms may
develop overnight as a low-level jet strengthens and overspreads the
stalled surface boundary across KS. Large hail could accompany this
activity later in the forecast period.

..Leitman.. 06/08/2026

$$