Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon Aug 28 2023 06:45:03

AWUS01 KWNH 280644
FFGMPD
GAZ000-281100-

Mesoscale Precipitation Discussion 0994
NWS Weather Prediction Center College Park MD
243 AM EDT Mon Aug 28 2023

Areas affected...Portions of Northern GA

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

Valid 280643Z - 281100Z

SUMMARY...A band of slow-moving showers and thunderstorms with
very heavy rainfall rates may produce isolated instances of flash
flooding through the predawn hours.

DISCUSSION...The latest radar imagery shows a band of rather
slow-moving showers and thunderstorms over areas of northern GA in
close proximity to a quasi-stationary front draped across the
region. The convection over the last couple of hours has been
tending to locally persist over the same area with some
backbuilding characteristics seen with some of the cells.

Cloud top temperatures have been seen cooling with some of the
thunderstorms east of Atlanta (ATL) and south of Athens (AHN) and
this suggests a persistence of locally strong updrafts that will
continue to favor areas of heavy rainfall for at least the next
few hours.

MLCAPE values are on the order of 500 to 1000 J/kg along the front
along with plenty of moisture with PWs up around 2 inches. This is
helping to facilitate very heavy rainfall rates with some of these
stronger cells, and MRMS data has shown rates up to 2.5
inches/hour.

The convection will likely tend to weaken closer toward dawn as
instability continues to be exhausted, but there is some broad
warm air advection that will continue ahead of a weak area of low
pressure advancing east along the front. This may allow for some
of the convection to persist in a disorganized fashion going
through dawn. Some spotty storm totals of 3 to 5 inches will be
possible by dawn where these storms tend to persist or backbuild.

Expect the potential for isolated instances of flash flooding and
especially if some of these slow-moving cells can make it into the
more urbanized locations near or in between Atlanta and Athens.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7C6nouQvkF2c3VIsBJQoiSKN8p7LftoBxNwJgQqvQqUC8WdRhXuvom9FybjdRN1iglEo=
3spFiiWtIoG3u5UVVLAi9Ac$  for graphic product...

ATTN...WFO...CAE...FFC...GSP...

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

LAT...LON   34318476 34308418 34208351 34078295 33908260=20
            33718239 33488248 33428295 33468369 33618451=20
            33908511 34188510=20

=3D =3D =3D
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