Mesoscale Precipitation Discussion 0646
NWS Weather Prediction Center College Park MD
548 PM EDT Wed Jul 08 2026

Areas affected...eastern NE into IA, southeastern MN and central
WI

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

Valid 082147Z - 090300Z

Summary...Training of thunderstorms is expected to lead to
isolated to scattered areas of flash flooding from portions of
northern IA into southeastern MN and WI over the next 3-5 hours.
Hourly rainfall of 1 to 2 inches (locally higher) is expected to
support totals of 2 to 4 inches with isolated totals over 5 inches
possible.

Discussion...2130Z radar imagery showed an axis of thunderstorms
aligned just north of a southward advancing outflow boundary
extending from near the WI/MN/IA tri-state border, westward to
where it intersected a stationary front near Fairmont, MN. MLCAPE
was estimated to range from 1500-2500 J/kg just south of the
outflow boundary with an anomalous PW axis of 1.7 to 2.0 inches in
place from northeastern NE into central WI (1 to 2+ standard
deviations above the mean), via 21Z SPC mesoanalysis data.

A positively tilted shortwave trough axis passing east through
south-central MN should continue to aid augmentation of
southwesterly low level flow from IA into WI. 850 mb wind speeds
are forecast by the RAP to increase into the 25-30 kt range from
northern IA into southeastern MN and western WI through 03Z. Mean
deeper layer steering flow oriented from west to east will promote
training of cells, at least initially. As cells congeal and form
clusters, there is potential for more southward propagation
following forecast Corfidi vectors. This type of pattern would
tend to favor the greatest training potential along the western
flank of outflows. Meanwhile additional convective development is
expected farther upstream across eastern NE into IA near the cold
front aided by upstream shortwave energy over northern NE,
advancing east. While timing is a bit uncertain, there will be the
potential for cells to line up just ahead of the cold front with
potential for brief west-east training as cells advance downstream
toward the east/southeast.

Flash flooding from hourly rainfall of 1 to 2+ inches and storm
totals of 2 to 4+ inches should be expected in a few locations
from eastern NE into IA, southeastern MN and into central WI.

Otto

ATTN...WFO...ARX...DMX...DVN...FSD...GRB...MKX...MPX...OAX...

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

LAT...LON   44699076 44638981 44318752 43638757 43378799
            43058965 42689102 41899305 41119707 41799753
            42429640 43449519 43999406 44519309 44659200