083
ACUS02 KWNS 111736
SWODY2
SPC AC 111734

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 PM CDT Tue Aug 11 2026

Valid 121200Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
CENTRAL ILLINOIS INTO LOWER OHIO VALLEY...AND PORTIONS OF THE
CENTRAL PLAINS...

...SUMMARY...
Thunderstorms with severe gusts and hail will be possible Wednesday
afternoon and evening across parts of the central and northern High
Plains. Damaging gusts and isolated hail will also be possible
across parts of the Midwest and Ohio Valley.

...Illinois/Lower Ohio Valley...
Forecast uncertainty remains high for these regions. Morning
convection, or lack thereof, will influence the location/magnitude
of afternoon severe potential. At least modest southwesterly flow at
low levels is expected to continue into Wednesday morning. It is at
least plausible that the boundary within Iowa/Illinois remains
stationary or makes only modest southward progress. Weak warm
advection may promote elevated storms in northern Illinois by mid
morning. These storms could produce large hail and isolated wind
damage. Into the afternoon, this activity could have a tendency to
develop southward into a very moist, destabilizing airmass in the
Lower Ohio Valley. Another possibility is the development along the
surface boundary during the afternoon. The eastward progress of
storms will likely be limited as substantial impact from convection
is anticipated from Tuesday afternoon/evening. Steep mid-level lapse
rates and 40-45 kt of effective shear will allow for organized
storms capable of isolated large hail and damaging winds. Damaging
winds are expected to be the main threat as upscale growth is
expected to occur quickly. The 15% Wind/Slight Risk has been
adjusted northward and eastward to account for trends in guidance
and expected airmass destabilization.

...Central Plains...
Moist, easterly flow north of a developing surface low in eastern
Colorado/western Kansas will allow for moderate to strong
destabilization across parts of Nebraska/southern South Dakota.
Steep mid-level lapse rates and moderate to strong effective shear
will promote supercell development from near the Black Hills to
southwestern Nebraska. Large hail and isolated severe wind gusts
would be possible initially. Some intensification of the low-level
jet may lead to upscale growth into one or more linear segments
moving eastward. The potential for a more organized MCS is not clear
given the low-level jet will be focused farther east. Elevated
storms associated with the low-level jet core are possible in
eastern Nebraska/western Iowa where large hail and isolated wind
gusts may occur.

...North Dakota into Wisconsin Michigan...
Modest destabilization is expected farther north into the northern
Plains and Upper Midwest/Great Lakes. Sufficient mid-level flow will
be present for organized storms. The main questions will be storm
coverage and longevity. Isolated wind damage and large hail would
occur with the strongest, sustained storms.

...Carolinas/southern Appalachians...
Uncertainty in the evolution of early morning convection remains
relatively high. While an MCV from convection in the Ohio Valley may
impact parts of these regions, the timing of this feature may not
lend to an organized severe threat during the afternoon. The
Marginal risk will be maintained this outlook cycle for potential
isolated strong to severe storms. However, the potential for
sufficient airmaass destabilization continues to appear low.

..Wendt.. 08/11/2026

$$