From LOT. This is interesting
.DISCUSSION...
Issued at 130 PM CDT Fri Aug 14 2026
...THREAT FOR SIGNIFICANT FLASH FLOODING TONIGHT...
Early afternoon surface charts depict an elongated stationary
front extending from central Virginia along the Ohio River
northwestward toward Kansas City, Missouri. A series of mid-
level perturbations are riding along and north as the front as
evident by festering areas of showers and thunderstorms from
Omaha, Nebraska to Indianapolis, Indiana. The western-most
perturbation (near Omaha) is the strongest in the region, as
demonstrated by broad anticyclonic upper-level venting depicted in
mid-level water vapor imagery as well as a clear cyclonic low-
level circulation (a "warm-core" low) being sampled by both
KOAX/KDMX WSR-88D radars.
This evening, the Omaha warm-core low pressure system will
shift eastward and encounter an increasingly unstable airmass
(MUCAPE > 3000 J/kg) across southern Iowa. Rapid thunderstorm
development and associated regions of latent heat release will
be poised to intensify the warm core low west of the Mississippi
River by midnight, leading to augmented low-level moisture
transport north of the stalled front and into the circulation.
Intense moisture convergence will lead to unusually high
tropical-like moisture values with mean PWATs forecasted to
approach 2.5" (near all-time records per sounding climatology at
ILX/DVN) ahead of the low. Taken altogether, a cluster of
thunderstorms with intense rain rates (3 to 5"/hr) is expected
to develop and move into northern Illinois during the pre-dawn
hours of Saturday morning. (This process is not unlike how
tropical systems intensify and produce intense rain rates).
While the center of the warm core low is expected to track more
or less along the I-88 or I-80 corridors during the morning
hours, the west-to-east orientation axis of the instability axis
south of the core should promote the highest coverage of
thunderstorms near and south of I-80. The thunderstorms are
expected to reach the I-39 corridor sometime in the 1 to 3 AM
timeframe, and then the I-55 and I-57 corridors sometime in the
2 to 5 AM timeframe, and then northwestern Indiana after 5 AM.
The back edge of thunderstorms would then work eastward through
the area after daybreak, perhaps not clearing northwestern
Indiana until the 10 AM to 1 PM timeframe.