807
ACUS02 KWNS 041732
SWODY2
SPC AC 041730

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Thu Jun 04 2026

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL AND
EASTERN NEBRASKA...NORTH KANSAS...MUCH OF IOWA...SOUTHEAST
MINNESOTA...AND FAR WESTERN WISCONSIN...

...SUMMARY...
Scattered severe storms capable of large to very large hail,
damaging winds with potentially significant gusts, and perhaps a
couple of tornadoes are expected Friday afternoon into night across
portions of the central Plains into upper Great Lakes.

...Synopsis...
A weak mid-level shortwave trough in the western Great Lakes Friday
morning is forecast to weaken as it moves eastward through the day.
A mid-level ridge will build across the central/northern Plains
through the day with a strong trough approaching the Northwest. At
the surface, high pressure will move off the Southeast coast with
weak lee troughing across the central High Plains vicinity within an
otherwise nebulous surface pattern.

...Central Plains into the Upper Midwest...
Thunderstorms will be ongoing at the beginning of the period, likely
from northern Missouri into Iowa and southeast Wisconsin. Strong
instability is expected to develop south/west of this activity where
steep lapse rates advect over a moist airmass featuring low 70s
dewpoints. Height rises across this region (southeast Nebraska into
southwest Iowa) cast some doubt on diurnal storm development.
Several members of the 12Z HREF show storms developing within this
zone, but most others (most notably the HRRR, do not). Therefore,
while the environment would support strong supercells with a threat
for very large hail, damaging winds, and perhaps a tornado, the
uncertainty related to storm coverage precludes higher probabilities
at this time.

Regardless of if afternoon storms develop, additional convection is
expected during the evening as the low-level jet strengthens. These
storms may initially begin as supercells, but will likely grow into
a linear segment relatively quickly. Given the strengthening
low-level jet and forecast soundings that do not show clearly
elevated thermodynamic profiles, expanded the 2% tornado
probabilities east to account for some tornado threat during the
evening hours.

Additional storms are possible farther northeast from northeast Iowa
into Wisconsin along a diffuse cold front. While mid-level flow (and
thus deep-layer shear) will be stronger across this region,
instability is forecast to be more limited due to that
morning/previous night convection that moved across the region and a
lack of a strong low-level moisture advection into the region.
Therefore, some strong to isolated severe storms are possible, but
may be too isolated/marginal for higher probabilities at this time.

..Bentley.. 06/04/2026

$$