586 

AWUS01 KWNH 140347
FFGMPD
MIZ000-WIZ000-IAZ000-140800-

Mesoscale Precipitation Discussion 0102
NWS Weather Prediction Center College Park MD
1145 PM EDT Mon Apr 13 2026

Areas affected...southern WI into central/northern Lower MI

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

Valid 140344Z - 140800Z

Summary...Areas of flash flooding will be likely from southern WI
into central/northern Lower MI over the next 4-5 hours. Saturated
to nearly saturated soils are expected to be a contributing factor
to excess runoff from rainfall rates of 1-2 in/hr.

Discussion...0320Z radar imagery across the Upper Midwest showed
an MCS with an elongated convective line on its southern flank,
oriented west-east from the MN/WI/IA tri-state region into
northwestern Lower MI. The cluster of thunderstorms were located
along a quasi-stationary front that extended west to east through
central WI/MI with 500-2000 J/kg MLCAPE (highest over northeastern
IA, lowest over Lower MI) estimated just south of the boundary per
03Z SPC mesoanalysis data. Infrared imagery showed cloud tops
continued to cool with divergence aloft aided within the
right-entrance region of a 110-130 kt upper level jet streak
positioned over Lake Superior into southern Quebec. 850 mb VAD
wind data showed 50-60 kt of SSW flow from eastern IA into
northern IL and southern WI, aiding rapid moisture transport
across Lake Michigan into Lower MI with upstream moisture over the
Midwest between 1.2 and 1.4 inches.

As the main surface low along the front in northwestern IA
advances ENE tonight, continued southerly flow ahead of the low
into the ongoing complex of storms should sustain convection
within the unstable airmass for several more hours. Mean cell
motions from the W to SW will interact with the southerly low
level inflow allowing for segments of the line to advance
southeastward at times. Cell mergers and training within the
linear segments of the MCS will attain rainfall rates of 1-2 in/hr
at times with an overall movement toward the east through 08Z.
Most soils across the region are saturated due to snowmelt and/or
recent rainfall, with additional heavy rainfall more quickly
translating into runoff compared to average. Therefore, areas of
flash flooding are likely to occur across southern WI into Lower
MI over the next 4-5 hours.

Otto

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

ATTN...WFO...APX...ARX...DTX...GRB...GRR...MKX...

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

LAT...LON   45818459 45288327 44528305 43748367 42798585
            42498773 42528950 42719070 43409120 44019101
            44319034 44578902 45028737 45468637