768
AWUS01 KWNH 171015
FFGMPD
WIZ000-MNZ000-IAZ000-NEZ000-SDZ000-171430-

Mesoscale Precipitation Discussion 0452
NWS Weather Prediction Center College Park MD
614 AM EDT Mon Jun 17 2024

Areas affected...eastern NE/southeastern SD into IA, southern
MN/western WI

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

Valid 171014Z - 171430Z

Summary...Occasional areas of training will continue a threat for
flash flooding across portions of eastern NE/southeastern SD into
IA, southern MN and far western WI this morning. Rainfall rates of
1 to 2+ in/hr will be possible with additional totals of 2-4
inches.

Discussion...A broad MCS over portions of the Central Plains/Upper
Midwest has undergone a complex evolution over the past few hours
with a leading convective line extending from southeastern MN into
northwestern IA and eastern NE. Movement of the leading line has
been toward the east (northern portions) and southeast (southern
portions). Upstream re-development continued as well, with cloud
top cooling over northern NE, but appearance on radar imagery has
been somewhat fragmented. The entire system was post-frontal,
driven in part by a moderately strong low level jet of 35 to 60 kt
(highest over KS/NE) overrunning the slow moving front. 09Z SPC
mesoanalysis data showed MUCAPE of 500 to 2000+ J/kg in place from
the SD/NE border into southern MN and western WI. Aloft, flow was
strongly divergent and diffluent within the right entrance region
of a 130 kt centered over northern MN.

An overall eastward motion is expected to continue with the
convective complex over the next 3-4 hours but the greatest
potential for training will be from northeastern NE into portions
of IA and perhaps southern MN. It is here where mean eastward
motion of cells will have the best possibility of intercepting
subsequent development immediately downstream given placement of
the low level jet core. RAP guidance is forecasting weakening of
850 mb winds between 13-15Z along with weakening
divergence/diffluence aloft as the upper jet max translates into
southern Canada. Through ~14Z, a localized flash flood threat will
remain across eastern portions of the Central Plains into the
Upper Midwest.

Otto

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

ATTN...WFO...ARX...DMX...DVN...FSD...GID...LBF...MPX...OAX...
UNR...

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

LAT...LON   44429201 44279109 43789097 42699164 41809311
            41289468 41179615 41489760 41569792 42069848
            42309901 42619964 42780023 43030041 43469986
            43559764 43719606 44369321