042 

AWUS01 KWNH 160234
FFGMPD
MIZ000-INZ000-WIZ000-ILZ000-160800-

Mesoscale Precipitation Discussion 0111
NWS Weather Prediction Center College Park MD
1033 PM EDT Wed Apr 15 2026

Areas affected...Northern IL...Far Southeast WI...Southern L.P. of
MI...Far Northwest IND...

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

Valid 160235Z - 160800Z

SUMMARY...Potential for localized flash flooding continues through
the early overnight period; though coverage should become more
scattered with loss of heating/rainfall intensity.  Rates of
1.5-1.75"/hr and spots of 2-3" remain possible.

DISCUSSION...Regional RADAR depicts a mature MCV across central
Lake Michigan just east of Milwaukee progressing toward
Holland/Muskegon, MI with a trailing QLCS convective line
extending across SE WI into the NW Exurbs of Chicago along W I-88
in N IL toward the Quad Cities.  The cold pool appears to be
maturing as well, increasing forward propagation of the line
particularly through the middle, toward the WI/IL line, this is
reducing overall residency time for extreme rainfall totals, but
the short-term heavy bursts may still result in 1-1.5" in 30 to 60
minutes.  Given recent heavy rainfall and saturated upper soil
profiles and proximity to hydrophobic urban conditions near
Chicago will result in increased run-off and likely incidents of
localized flash flooding/rapid rise flood, especially in the next
few hours.

GOES-WV shows expanding divergence region along the entrance of a
100 kt 3H speed max across the LP of MI at this time, helping to
maintain the MCV crossing the more stable air of Lake Michigan but
solid southwesterly warm-air advection is allowing for downstream
convergence with limited but sufficient MUCAPE of 500-750 J/kg.
VWP shows solid 850-700 40-45kt flow at the western nose of the
deep layer moisture axis where overall PW totals are increasing to
over 1.25".  This will likely continue to support 1.5-1.75"/hr
rates and given the record wet spring across the SW LP; FFGs are
compromised in spots and while typically sandy and able to absorb
these rates and totals up to 2-3", saturation over 75% to 85% will
still quickly be overwhelmed with above normal run off and
potential for localized flash flooding conditions.   However,
proximity to the unstable air will be increasing (along with
overall diurnal loss) and overall intensity of thunderstorms will
be steadily increasing through the night reducing overall coverage
and magnitude of flooding potential.

Gallina

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

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

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

LAT...LON   43868583 43758458 43508280 42468379 41648587
            41268769 41238976 41499024 42108976 42648902
            42968835 43578710