Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Apr 05 2023 08:23:52

AWUS01 KWNH 050823
FFGMPD
TNZ000-KYZ000-ILZ000-MOZ000-ARZ000-051200-

Mesoscale Precipitation Discussion 0156
NWS Weather Prediction Center College Park MD
423 AM EDT Wed Apr 05 2023

Areas affected...Northeastern AR...Southeastern MO...Far Southern
IL

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

Valid 050822Z - 051200Z

Summary...Strong to severe thunderstorms with localized rainfall
rates of 1-2"/hr may result in localized totals of 2-4 inches,
isolated instances of flash flooding through early morning.

Discussion...Semi-discrete, deep convective activity has begun to
proliferate across an axis of elevated surface dewpoints/theta-e
oriented from northeast AR into southeast MO early this morning.
Convective initiation over the past several hours has been
coincident with the erosion of a capping inversion (with SBCIN
going from -50 J/kg to near 0 J/kg across west-central AR). The
mesoscale environment is otherwise characterized by SBCAPE of
1000-2000 J/kg, precipitable water of 1.4-1.8 inches (at or above
the max moving average per LZK sounding climatology), and deep
layer (0-6 km) shear of 50-60 kts. Favorably curved hodographs
(per KLZK and KNQA VWPs) suggest that supercell storms will favor
right-moving northeasterly tracks of 45-50 kts. This motion is
only slightly offset (to about 10 degrees to the east of) the
850-300 mb mean wind, suggesting the potential for some repeating
of 1-2"/hr rainfall rates as cells track nearly parallel to a
(significantly) trailing cold front about 200 miles to the west.
The CAMS (including the 00z HREF suite and subsequent HRRR runs)
are handling the ongoing convection very poorly, but short-term
observational trends suggest the potential for localized instances
of flash flooding (as repeated 1-2"/hr rates may lead to some
localized totals as high as 2-4" through 12z).

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!45-UNi-V2uQ8YHlAkPmnwuCzZE1AVA2eXdFoGx67jjRWyfdux6Rn20-PRioF0IRbOJxK=
zb5pzrzX38pSfPIQa4VPPpA$  for graphic product...

ATTN...WFO...LSX...LZK...MEG...PAH...SGF...

ATTN...RFC...ABRFC...LMRFC...NCRFC...OHRFC...NWC...

LAT...LON   38118945 37488873 36378946 35819003 35569046=20
            35409079 35299127 35259178 35259234 35559274=20
            36509207 37649083=20

=3D =3D =3D
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