571
ACUS01 KWNS 111256
SWODY1
SPC AC 111254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Fri Jul 11 2025

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST
AND CENTRAL HIGH PLAINS...

...SUMMARY...
Severe thunderstorms are expected this afternoon and evening across
the Midwest to southern portions of the Great Lakes region,
accompanied by a risk for damaging wind gusts, hail, as well as some
tornado potential. Severe thunderstorms are also expected across the
central/southern High Plains and Upper Midwest.

...Midwest/Lower Missouri Valley to Great Lakes...
A decayed overnight MCS and residual convection/cloud cover will
reinforce the baroclinic zone regionally. Near/south of the
boundary, surface dew points near and above 70F, beneath modestly
steep mid-level lapse rates, are forecast to contribute to CAPE on
the order of 2000-3000 J/kg. This will be beneath a lingering belt
of convectively augmented mid-level flow (on the order of 30-50 kt
in the 700-500 mb layer). Coupled with modest, clockwise-curved
low-level hodographs in advance of a weak surface wave, the
environment should become conducive to supercell structures into
mid/late afternoon. These supercells may pose a risk for hail and
potentially a couple of tornadoes across parts of northern Missouri
and southern/eastern Iowa into northern Illinois, and possibly far
southern Wisconsin. Damaging wind gusts should become the more
predominant potential hazard as convection tends to grow upscale
into east/southeastward-moving clusters this evening.

...Central High Plains...
The immediate post-frontal regime should be favorable for severe
storm development this afternoon into evening across southeast
Wyoming and northeast Colorado into southwest Nebraska/northwest
Kansas. Some initial supercells capable of large hail can be
expected, and one or more east/eastward-moving clusters may evolve
by evening with severe-caliber winds also a possibility.

...Upper Midwest...
At least isolated strong to severe thunderstorms can be expected
near the east/southeastward-moving front this afternoon, including
the eastern Dakotas into much of Minnesota. This will be influenced
by the amplifying upper-level trough approaching the
Dakotas/northern Minnesota. The strongest winds aloft/vertical shear
will tend to lag the front, but ample near/pre-frontal buoyancy will
support storms capable of hail/wind.

...Southern Rockies into the Great Plains...
Thermodynamic profiles characterized by modest low-level moisture,
but with generally steep lapse rates, including fairly deep
boundary-layer mixing, may become conducive to scattered
thunderstorm clusters posing a risk for severe wind and hail late
this afternoon and evening. A degree of storm organization may be
aided by modest shear beneath northwesterly mid-level flow, with
thunderstorm activity mostly initiating off the higher terrain of
the Front Range through Sangre de Cristo Mountains. Additionally,
low-level convergence within surface troughing across southern
Kansas through the Oklahoma/Texas Panhandle vicinity may also become
sufficient for thunderstorm initiation during the peak late
afternoon heating, and one or more semi-organized clusters capable
of wind damage could evolve. This region will be reevaluated in
subsequent outlooks for potential inclusion of a wind-related Slight
Risk.

..Guyer/Bentley.. 07/11/2025

$$