Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Jan 03 2023 00:33:21

AWUS01 KWNH 030033
FFGMPD
MSZ000-LAZ000-ARZ000-030531-

Mesoscale Precipitation Discussion 0005
NWS Weather Prediction Center College Park MD
732 PM EST Mon Jan 02 2023

Areas affected...northern Louisiana, southeastern Arkansas,
western Mississippi

Concerning...Heavy rainfall...Flash flooding likely

Valid 030031Z - 030531Z

Summary...A complex of training convection has been producing
intense rainfall rates exceeding 3 inches per hour at times.  This
scenario should continue northeastward through the Ark-La-Miss
over the next several hours, likely causing flash flooding.

Discussion...An intense, lead supercell has materialized within an
unstable and weakly capped warm sector across much of the Lower
Mississippi Valley this evening.  That lead cell - now over Union
Parish, Louisiana, continues to move north-northeastward in
parallel with mid/upper steering flow within a very moist,
strongly sheared pre-convective airmass characterized by 1.6 inch
PW values and roughly 2000 J/kg SBCAPE.  Immediately upstream of
that lead supercell, loosely organized convection has repeated
over the same areas impacted by the lead supercell within a
similarly unstable environment.  The lack of rightward propagating
with the upstream cells and continued, efficient rainfall
processes have led to 2-3 inch/hr rainfall rates at times (3-4.5
inches in 3 hours) along with reports of water over roads and
localized flash flooding.  Moderate to high MRMS Flash responses
have also been noted especially southwest of Monroe.

The storms themselves remain in a weakly capped warm sector.=20
Marginal forcing for ascent aloft is in place, with most of the
development being driven by confluent warm-sector flow and
re-initiation of updrafts along convective outflows near the
complex.  Indications are that this ongoing scenario should result
in continued 1.5-3 inch/hr rainfall rates that will both locally
exceed FFG thresholds in the region and allow for continued flash
flood impacts downstream.  Heavier rainfall is crossing the
Arkansas/Louisiana state line into Union and Ashley Counties and
should reach the Mississippi River near Bolivar County over the
next 2 hours (through 230Z or so).  Upstream areas of
north-central Louisiana currently experiencing impacts from heavy
rainfall will probably experience another round of convection
after 02Z as newer cells form near/south of Lufkin, Texas.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-4wEfEK2H19z50n38vlx0B5wv2HSxoesW4GrhTHJ3DKmLViS2PVR5Jk08dWeVLHmDVxw=
85HutaYF9HW6muvydZhs6KM$  for graphic product...

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

ATTN...RFC...LMRFC...NWC...

LAT...LON   34838994 34159002 33289064 32819110 31929199=20
            31579321 32489306 33239257 34299160 34819096=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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