Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Jul 16 2023 22:10:25

AWUS01 KWNH 162210
FFGMPD
ALZ000-MSZ000-LAZ000-170300-

Mesoscale Precipitation Discussion 0750
NWS Weather Prediction Center College Park MD
609 PM EDT Sun Jul 16 2023

Areas affected...Louisiana and Southern Mississippi

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

Valid 162206Z - 170300Z

SUMMARY...Organized clusters of heavy thunderstorms will continue
over portions of Louisiana and southern MS/AL this evening.
Scattered instances of flash flooding are expected to continue.

DISCUSSION...An MCS that spread from northwest LA is converging
with slow moving cells that have developed along the central LA/MS
border and pose an imminent threat of flash flooding with rain
rates of 2-3" over areas that just received heavy rain. Additional
thunderstorm clusters which also produced hourly rainfall of 2-3"
and are slow moving are centered just west of New Orleans and
Mobile, AL.

Ample instability and moisture lead to the develop of this
activity, but the initial activity that developed this afternoon
along the MS/LA border is now directly ahead of the MCS coming
from central LA, so uncertainty exists as to how the MCS will
reach to the outflow cooled air. Recent HRRRs struggle with
initializing the activity properly, so they do not provide
confidence in the question as to how the MCS will behave. Ample
instability is still present over south-central MS, north of the
previous rainfall footprint, and the MCS cold pool does have an
eastward trajectory that is currently approaching the northern
MS/LA border, so further development along the north side is
likely and the presence of the previous boundary, which is
parallel to westerly 15kt deep layer mean flow, could allow
training and flash flood risk into south-central MS and then
farther downstream to Mobile.

Scattered instances of flash flooding are expected early this
evening and may continue into later this evening should activity
persist around/over that previous rainfall footprint over southern
MS/southeast LA.

Jackson

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6Enh5rBVuI1Xz5Azt0xA93UHClZ4LEoYqW1GYUPC9WOVorTT8dwOu-Tcodwmd7zk2Xd9=
EjvgnXIBOQN688c0dvbFx9I$  for graphic product...

ATTN...WFO...JAN...LCH...LIX...MOB...SHV...

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

LAT...LON   32039166 31989084 31788994 31298771 30268800=20
            29818965 29589009 29949106 30699218 31419218=20
            31879203=20

=3D =3D =3D
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