Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun May 11 2025 19:33:27

AWUS01 KWNH 111932
FFGMPD
ALZ000-MSZ000-120130-

Mesoscale Precipitation Discussion 0254
NWS Weather Prediction Center College Park MD
331 PM EDT Sun May 11 2025

Areas affected...Central to Southeast MS...Central and Western AL

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

Valid 111930Z - 120130Z

SUMMARY...Developing bands of showers and thunderstorms will tend
to expand in coverage going through early this evening. Some
cell-training with heavy rainfall rates and also moist antecedent
conditions will favor a threat for isolated to scattered areas of
flash flooding.

DISCUSSION...The mid-afternoon GOES-E visible satellite imagery
shows a developing CU/TCU field across much of central to
southeast MS and through western AL as diurnal heating/solar
insolation work to destabilize the boundary layer in close
proximity to a frontal occlusion. In fact, LightningCast data
coupled with radar imagery does show convective initiation taking
place with a few small-scale bands of convection beginning to
organize over eastern MS and western AL

A deep layer trough/closed low continues to pivot across the lower
MS Valley, and this deep layer cyclonic flow coupled with the
improving thermodynamic environment should support developing and
expanding bands of convection going through the early evening
hours.

MLCAPE values have risen to as much as 1000 to 1500 J/kg with
3-hour CAPE differentials of 600+ J/kg and this coupled with an
expected increase in moisture convergence near the frontal
occlusion should set the stage for convection that will be capable
of producing rainfall rates of 1 to 2 inches/hour along with
concerns for cell-training given the unidirectional deep layer
cyclonic flow.

The most recent 12Z HREF guidance along with recent HRRR and RRFS
solutions support the potential for some bands of convection to
produce rainfall amounts through early this evening of 2 to 4
inches. These rains coupled with the moist and locally wet
antecedent conditions will favor a setup that may yield isolated
to scattered areas of flash flooding and especially where any
cell-training occurs.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!40BjZmTCG-9k0PUnZylJS3HLlMlPI7F1UH2yybxvcJhEmxLuuA96ZBvrUiEJdAZB7IeN=
QVFwNqII89Kx2OxixplWu0A$  for graphic product...

ATTN...WFO...BMX...JAN...MEG...MOB...

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

LAT...LON   34438949 33938803 32938714 32168694 31398723=20
            31078770 30928820 31138885 31718922 32348971=20
            33519061 34159056=20

=3D =3D =3D
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