Mesoscale Precipitation Discussion 0497
NWS Weather Prediction Center College Park MD
432 PM EDT Mon Jun 23 2025

Areas affected...southeastern Minnesota, northeastern Iowa,
central/southern Wisconsin, far northern Illinois

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

Valid 232031Z - 240231Z

Summary...Scattered thunderstorms are increasing in organization
and intensity across southeastern Minnesota and western Wisconsin,
with areas of 1-1.75 inch/hr rain rates now being observed.  These
rates will promote isolated/spotty flash flood potential across
the discussion area through 02Z/10pm CDT this evening.

Discussion...Thunderstorms were increasing in coverage and
intensity - especially across southeastern Minnesota where 1-1.75
inch/hr rain rates were estimated per MRMS.  The cells are
embedded in deep southwesterly flow aloft along with weak/modest
low-level shear, suggesting outflow-dominance and potential for
multiple cell mergers to locally prolong rain rates.  The cells
are in a strongly unstable, moist airmass (3000 J/kg MLCAPE, 2
inch PW values), supporting intense and efficient downdrafts and
local rain rates exceeding 2 inches/hr.  These rain rates will
approach/locally exceed FFG thresholds, supporting isolated flash
flood potential in the near term.

Eventually, cells will further congeal into one or two
forward-propagating convective complexes over the course of the
afternoon.  The upscale growth should allow for continued heavy
rain potential along with more of a southward component of
translation/development of heavy rain axes into more of southern
Wisconsin, northeastern Iowa, and adjacent areas.  The uncapped
airmass southeast of ongoing convection and broad low-level
confluence/convergence suggests that newer convection will merge
with evolving complexes and aid in continued heavy rain potential,
with spots of 2 inch/hr rain rates continuing.  Isolated instances
of flash flooding are expected through the evening as a result.

Cook

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

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

LAT...LON   44778792 43838768 43048803 42368880 41969068
            41649296 42329364 43279343 44019256 44679043