722
AWUS01 KWNH 102131
FFGMPD
MIZ000-INZ000-WIZ000-ILZ000-IAZ000-110330-

Mesoscale Precipitation Discussion 0056
NWS Weather Prediction Center College Park MD
530 PM EDT Tue Mar 10 2026

Areas affected...Extreme Southeast WI...Northern IL...Northwest
IN...Southwest Lower MI

Concerning...Heavy rainfall...Flash flooding possible

Valid 102130Z - 110330Z

SUMMARY...Strong to severe thunderstorms will develop and increase
in coverage this evening. High rainfall rates of 1 to 2
inches/hour coupled with cell-training concerns will drive a
threat for flash flooding, including for the Chicago metropolitan
area, going into the evening hours.

DISCUSSION...The latest RAP analysis along with surface
observations shows a quasi-stationary front draped from southeast
IA through northern IL and into southern Lower MI. Multiple waves
of low pressure are transiting the front. Meanwhile, the boundary
layer along and south of the front continues to rapidly
destabilize with MLCAPE values of 2000 to 3000 J/kg seen nosing up
across northeast MO through central IL. This is also occurring
ahead of a wave of low pressure over southern IA.

Upstream shortwave energy along with the eastward advance of this
surface low will drive the development and expansion of strong to
severe thunderstorms across sizable areas of the Midwest over the
next several hours. This convection is then expected to gradually
evolve into a couple of larger scale MCS clusters this evening.
The 18Z HREF guidance and recent special RAOB soundings shows a
strongly sheared kinematic environment, including along the
aforementioned front, which coupled with the available instability
should strongly support supercell thunderstorms at least
initially. Cell-mergers and upscale growth of MCS activity will
favor heavy rainfall totals in addition to the severe hazards.

Rainfall rates of 1 to 2 inches/hour are expected which will be
aided by a strong low-level jet of 40 to 50+ kts. This enhanced
moisture and instability transport into the front should persist
well into the evening ahead of the approaching low center which
will favor convective sustenance. Cell-training concerns will
exist in time given nearly parallel alignment of the deeper layer
steering flow with the front. This will support concerns for as
much as 2 to 4 inches of rain locally which will drive a threat
for areas of flash flooding.

This threat will extend across the more urbanized locations
including the Chicago metropolitan area. The primary concern for
excessive rainfall totals for this period will be across northern
IL, but expect northwest IN and southwest Lower MI to also see
this threat materialize late this evening and into the overnight
period.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...DVN...GRR...ILX...IWX...LOT...MKX...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON   42718717 42588590 41908557 41268601 40648747
            40488904 40759037 41419074 42089016 42548857