Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Mar 31 2023 18:33:01

AWUS01 KWNH 311832
FFGMPD
WIZ000-ILZ000-MOZ000-MNZ000-IAZ000-010031-

Mesoscale Precipitation Discussion 0146
NWS Weather Prediction Center College Park MD
232 PM EDT Fri Mar 31 2023

Areas affected...much of Iowa, southwestern Wisconsin,
southeastern Minnesota, far northern Missouri, and northwestern
Illinois

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

Valid 311831Z - 010031Z

Summary...A few areas of flash flooding is possible as storms
increase in coverage while migrating in from the southwest.

Discussion...Vigorous convective development has been observed
along an axis from south of Des Moines to near Kansas City over
the past half hour.  A separate cluster of storms was located in
northeastern Missouri also.  The storms are in a very unstable
environment characterized by nearly 3000 J/kg SBCAPE and strong
(7-8.5C/km) mid-level lapse rates.  Flow aloft was also quite fast
- exceeding 70 knots at 500mb from the southwest.  Localized
training of cells has contributed to a couple spots of 1+ inch/hr
rain rates (MRMS-estimated) south-southwest of Des Moines,
although fast storm motions have generally limited rainfall rates
in most areas in the short term.

The concern with the evolving scenario is that the combination of
1) forcing for ascent with an approaching mid-level trough axis
over northeastern Kansas and 2) minimal inhibition aloft will
result in scattered to numerous coverage of convection through the
afternoon.  Despite the fast storm motions, repeated/training
convection is likely to occur given the sheer number of storms
expected across the area.  This could result in additional areas
of 1+ inch/hr rainfall rates (perhaps 2-2.5 inches in 3 hours)
that could cause localized flash flooding over time as FFG
thresholds are exceeded.  Storms should continue to expand in
coverage while reaching the Mississippi River area (bordering Iowa
and Wisconsin) potentially as early as 23Z or so.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!4NWMwvpeRA3i7zz2Or3ZDDXBQflnyNzl-w1G_tdvkVjac3_-6ABriSKJRajx8OLT_IaP=
5_68OD68egHFWTn8tjPvxxw$  for graphic product...

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

ATTN...RFC...MBRFC...NCRFC...NWC...

LAT...LON   44419069 44198936 42988906 41428961 40439099=20
            40289367 40659434 41929481 42639476 43529399=20
            44329232=20

=3D =3D =3D
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