AWUS01 KWNH 021139
FFGMPD
WIZ000-MNZ000-IAZ000-021600-

Mesoscale Precipitation Discussion 0563
NWS Weather Prediction Center College Park MD
738 AM EDT Thu Jul 02 2026

Areas affected...Southern MN...Southern WI...Northeast IA

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

Valid 021140Z - 021600Z

SUMMARY...Thunderstorms with a history of producing flash flooding
will continue this morning for at least a couple more hours.
Additional areas of flash flooding are possible.

DISCUSSION...An outflow boundary oriented WNW-ESE remains the
trigger for thunderstorms that are in a ripe environment to
produce Excessive Rainfall rates. While instability is decreasing
to the north where rain-cooled air is beginning to weaken the
theta-e gradient, along the IA/MN border and into southern WI,
MUCAPE remains solidly in the 1,000-2,000 J/kg range. PWs are also
between 1.8-2.0", thus placing them around or slightly above the
90th climatological percentile. 925mb winds over western IA are
oriented not quite orthogonal to the outflow boundary, but the
ongoing theta-e and MUCAPE gradient remains in place per RAP
mesoanalysis and these 925mb winds will continue to run into the
outflow boundary in a manner that helps to sustain ongoing
convection. Doppler Radar shows storms flaring up on the western
flank of the outflow boundary over northwest IA that could head
east into southeast MN and northeast IA this morning. With the
favorable meteorological parameters mentioned above, this provides
an optimal environment for at least a couple more hours worth of
Excessive Rainfall along the MN/IA border and into southern WI.

The gradual southward propagation of the outflow boundary is
likely to cause storms to form over northeast IA, including
training storms possible within the highlighted region. MRMS
15-minute rainfall rates have surpassed 0.5" at times in southwest
MN, suggesting at least 2"/hr rainfall rates have occurred within
the strongest storms. Some locations in southeast MN have already
received over 3" of rain between 08-11Z. Eventually, the rain
cooled air to the north and slightly cooler temps prior to strong
daytime heating to the south should start to weaken the theta-e
gradient and 925mb winds will relax by late morning, causing
storms to gradually dissipate. Until then, storms will likely
linger through mid-morning with storms producing around 2"/hr
rainfall rates (max rates up to 2.5"/hr). Many locations within
the highlighted threat area sport 1-hr FFGs that are as low as 2".
Given these reasons, additional areas of flash flooding are
possible this morning.

Mullinax

ATTN...WFO...ARX...DMX...MKX...MPX...

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

LAT...LON 44049217 44039165 43999120 43969095 43819016=20
43708951 43398908 43138897 42878902 42708915=20
42648928 42618962 42719035 42799131 42729208=20
42679293 42699336 42669367 42689389 42749429=20
43039426 43239426 43409419 43749389 44009307=20

$$
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