341 

AWUS01 KWNH 152148
FFGMPD
WIZ000-ILZ000-IAZ000-160246-

Mesoscale Precipitation Discussion 0108
NWS Weather Prediction Center College Park MD
547 PM EDT Wed Apr 15 2026

Areas affected...southern Wisconsin, northern Illinois

Concerning...Heavy rainfall...Flash flooding likely

Valid 152146Z - 160246Z

Summary...Thunderstorms will migrate eastward across wet/sensitive
areas from yesterday's rainfall especially across Wisconsin.
Flash flooding is likely.

Discussion...Scattered thunderstorms have organized along a
frontal boundary from just north of Dubuque to Des Moines.  The
storms are exhibiting linear organization so far in their
evolution, with forward propagation and 40-50 kt speeds generally
limiting their rainfall potential to around 1 inch/hr or less.
Flash flooding is possible on an isolated basis in the short term.

Over the next 1-4 hours, however, storms will migrate eastward
along a remnant outflow/frontal boundary extending east-west
across southern Wisconsin (generally from Sheboygan to Wisconsin
Dells).  As low-level flow increases over Illinois, convergence
along this boundary could result in additional convection
developing in southern/southeastern Wisconsin out ahead of the
ongoing quasi-linear complex.  This will increase potential for
training/mergers and prolonged rainfall rates in areas that have
already experienced 1-4 inches of rainfall yesterday near/north
and west of Milwaukee and across far northern Illinois.  FFGs are
less than 1 inch/hr in some spots and could readily be exceeded
where mergers take place.  Flash flooding is likely - especially
in sensitive areas that received rainfall/runoff issues late
yesterday and early today.

Cook

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

ATTN...WFO...ARX...DVN...GRB...LOT...MKX...

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

LAT...LON   44558947 44408783 43208786 42008773 41548866
            41449051 42319153 43979095