Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Jul 22 2025 16:31:22

AWUS01 KWNH 221631
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-222100-

Mesoscale Precipitation Discussion 0775
NWS Weather Prediction Center College Park MD
1230 PM EDT Tue Jul 22 2025

Areas affected...Carolina Piedmont into southern Appalachians

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

Valid 221629Z - 222100Z

Summary...Isolated to scattered areas of flash flooding will be
possible across the Piedmont of NC/SC into the higher terrain of
the southern Appalachians through late afternoon. Rainfall rates
of 1-2 in/hr and localized 2+ in/hr rates will become likely but
much of that rainfall may fall over a sub-hourly timescale leading
to rapid runoff.

Discussion...GOES East visible and regional radar imagery at 16Z
showed scattered showers over far northeastern NC into western NC,
embedded within an anomalously moist environment in place over the
southeastern U.S. PW values on 12Z RAOBs from GSO and FFC ranged
from 2.1 to 2.2 inches, near or above the climatological max for
the middle of July per SPC data, and while PW values in the
mountains are naturally lower, similar PW percentile values are
likely into the terrain. Current cloud cover is likely limiting
MLCAPE over the western portions of the Carolinas with 16Z SPC
mesoanalysis data showing ~500 J/kg or less, but peak surface
heating is still a few hours away.

With continued surface heating, short term RAP forecasts show
MLCAPE values increasing into the 500-1500 J/kg range through 22Z.
The combination of sufficient instability and high moisture
(tall/skinny CAPEs) will allow for high short term rain rates via
efficient rainfall production. Deeper layer mean flow is oriented
from the NW at 5-10 kt, weaker to the south, which should allow
for relatively slow moving cells. 1-2 inches of rain in 30-60
minutes will be possible in the stronger cells that develop which
could lead to isolated to scattered areas of flash flooding.

Otto

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!8OrzlZHAsvJ0sDMsJHvuWyTua5OTnB7Flb3nhfsLaR6kQsQ5g-hB4rL6RY7B-e2dowdB=
CmoEVlSzLZa6o6rxi81I0o4$  for graphic product...

ATTN...WFO...FFC...GSP...MRX...RNK...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON   36588221 36498148 35958064 35158079 34728210=20
            34368302 34188384 34288456 35088459 36278303=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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