Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Mar 12 2023 01:55:51

AWUS01 KWNH 120155
FFGMPD
TNZ000-MSZ000-ARZ000-TXZ000-OKZ000-120754-

Mesoscale Precipitation Discussion 0097
NWS Weather Prediction Center College Park MD
855 PM EST Sat Mar 11 2023

Areas affected...far southeastern Oklahoma, southern/central
Arkansas, northern Mississippi, far southwestern Tennessee

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

Valid 120154Z - 120754Z

Summary...Expanding convective coverage is expected over the next
2-4 hours, with areas of training expected to result in 1-2.5
inch/hr rainfall rates at times.  Flash flooding could occur in
this regime.

Discussion...A few thunderstorms have recently developed across
southeastern Oklahoma (just southeast of McAlester), with rainfall
rates already peaking at over 1 inch/hr per MRMS radar data.  The
storms are just on the cool side of a surface boundary/warm front
extending from McAlester southeastward to Texarkana and El Dorado,
Arkansas and Greenville, Mississippi.  Lift/low-level ascent along
this frontal zone combined with 6-7 C/km lapse rates were
supporting the developing convection, while 1-1.3 inch PW values
were supporting heavier rainfall.  Additionally, the development
of the cells along the warm front while parallel to zonal flow
aloft was allowing for localized training to materialize already,
yielding the heavier rainfall rates.  These storms are also in an
area of moist soils from prior rainfall over the past two weeks,
with 2-4 inches of rainfall estimated across Arkansas portions of
the discussion area over the past 72 hours.

The west-to-east development and training potential should
continue to unfold over at least the next two hours as convective
coverage expands.  This should set up localized areas of 2-4 inch
rainfall amounts at times beneath training convection especially
on the cool side of the boundary.  Eventually, the HRRR and other
CAMs suggest that upscale growth could occur with the storms,
potentially posing a limit on training potential where storms
begin to forward-propagate.  Despite the upscale growth, training
and 1-2.5 inch/hr rainfall rates will still be possible especially
in northern Mississippi after 04Z.  These rates are likely to
exceed the 1-2 inch/hr FFG thresholds across the region.  Flash
flooding is possible across the region through 08Z.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5OsWL9D76BIbL_b9v-vCwv4WevHIuh1TqBNqwX93mqe6Fb47hY381LlsTY0rLCHm5_SS=
KMx3fStUFrD6g8Va3UsdSGU$  for graphic product...

ATTN...WFO...JAN...LZK...MEG...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...SERFC...NWC...

LAT...LON   35319270 35279040 35078861 34648822 33908839=20
            33398961 33289150 33239380 33919506 34439562=20
            34819558 35119448=20

=3D =3D =3D
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