Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Dec 17 2023 10:18:17

AWUS01 KWNH 171017
FFGMPD
NCZ000-SCZ000-GAZ000-171600-

Mesoscale Precipitation Discussion 1202
NWS Weather Prediction Center College Park MD
515 AM EST Sun Dec 17 2023

Areas affected...southeastern Georgia, portions of South Carolina

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

Valid 171015Z - 171600Z

Summary...Deep convection over the Gulf Stream (about 50 miles
east of Jacksonville, FL) was in a very warm, moist environment
that was quickly advancing northward toward coastal portions of
the discussion area.  A heavy rain (and isolated flash flood)
threat should materialize in these areas through 16Z.

Discussion...A quickly deepening low pressure area was now
estimated at just below 996mb and located about 40 miles southwest
of CTY (Cross City, FL) per SPC Mesoanalyses.  East of the low,
strong warm advection was resulting in rapid, surface-based
destabilization especially over the Gulf Stream just east of
Jacksonville, FL, where SBCAPE values of 500-2000 were noted.=20
Storms in this unstable environment were lightning-producing and
exhibiting cooling cloud tops.  They were also training locally
and producing areas of 2+ inch/hr rain rates (estimated per MRMS).
 Their location over water indicates zero flash flood risk over
land areas in the short term.

Models/observations are in general agreement that these storms
(and others developing within the destabilizing airmass) will
gradually develop northward toward coastal areas of South Carolina
and Georgia especially as the aforementioned surface low
approaches the area from the southwest.  As this occurs, areas of
1-3 inch/hr rainfall rates will become more likely over land areas
- especially after around 12Z or so and across coastal areas where
the greatest instability will reside.  FFG thresholds across the
region are generally in the 2.5-4 inch/hr range across the
discussion area (locally lower), suggesting that any flash flood
threat should remain isolated and conditional upon heavier
rainfall occurring in urbanized or other sensitive ground
conditions.  The flash flood risk should gradually spread from
southwest to northeast across the discussion area in the 12-16Z
timeframe, and a few spots of 3-5 inch totals cannot be completely
ruled out.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-B_8GRoyFu9sYNkNlbhLI-fodbXDpuYjdzpliFtPD7TZpj1HiWxI3IJt_WOkMuGr-gyx=
yV5sMlFnMExWOcNWsNNO9iU$  for graphic product...

ATTN...WFO...CAE...CHS...FFC...ILM...

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

LAT...LON   34618019 34357880 33597815 32877861 32127998=20
            31498142 32118230 32798207 33638164 34358098=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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