Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Aug 25 2023 21:24:13

AWUS01 KWNH 252124
FFGMPD
KSZ000-NEZ000-COZ000-260322-

Mesoscale Precipitation Discussion 0978
NWS Weather Prediction Center College Park MD
523 PM EDT Fri Aug 25 2023

Areas affected...southern Nebraska, northern through western
Kansas

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

Valid 252122Z - 260322Z

Summary...Deep convection will continue to expand in coverage and
intensity along a frontal zone currently across far southern
Nebraska near the Kansas border.  Weak wind fields aloft will help
storms produce 1-2.5 inch/hr rain rates, resulting in a few areas
of flash flooding this afternoon and evening.

Discussion...Storms were developing quickly within a distinct
frontal zone very near the northwestern Kansas/southwestern
Nebraska border region over the past hour.  Despite storms
residing just north of the true surface front over northwestern
Kansas, point forecast soundings in the vicinity of McCook
indicate weak vertical wind profiles through the troposphere in
addition to surface-based instability exceeding 2500 J/kg and
minimal inhibition.  These factors, in addition to 1.5+ inch PW
values across most of the region were fostering 1-2 inch/hr rain
rates with cells especially across southwestern Nebraska.  With
similar atmospheric profiles (and newer convective development)
across northwestern and north-central Kansas, the expectation is
that these heavier rain rates will eventually materialize/spread
southeastward toward I-70 in Kansas over the next 2-4 hours.

With time, the surface boundary/frontal zone will spread southward
while providing a focus for additional, yet slow-moving
thunderstorms.  Weak/modest low-level shear should also provide
opportunity for multiple cell mergers and upscale growth into one
or more forward-propagating complexes.  Regardless of storm mode,
storm motions will remain sufficiently slow enough for several
areas of 1-2.5 inch/hr rain rates to materialize across a broad
part of western/northern Kansas through 03Z.  Despite minimal
rainfall across much of the region over the past couple weeks, FFG
thresholds in the 2 inch/hr range should be exceeded locally, with
at least an isolated flash flood risk materializing especially in
low-lying or sensitive areas.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!43itw943lkuKvHaKOLofPmJzXwQC7awMoxHM1R6iOZswUXyDjmVyVAJSZOSjWRz1Cpkc=
1cFt10KDx7FnHwmqaBx_srw$  for graphic product...

ATTN...WFO...DDC...GID...GLD...ICT...LBF...OAX...PUB...TOP...

ATTN...RFC...ABRFC...MBRFC...NWC...

LAT...LON   41109887 40249708 39409693 38359822 37139981=20
            37180193 38380218 40380202 41020096=20

=3D =3D =3D
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