Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Jul 31 2025 17:03:50

AWUS01 KWNH 311702
FFGMPD
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-KYZ000-312200-

Mesoscale Precipitation Discussion 0833
NWS Weather Prediction Center College Park MD
102 PM EDT Thu Jul 31 2025

Areas affected...West Virginia...Northeast Kentucky...Adj
Southeast OH, Southwest PA, & Far Western MD...

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

Valid 311700Z - 312200Z

SUMMARY...Quick moving cold frontal convection with sub-hourly
1-2" totals pose widely scattered localized flash flooding across
steeper terrain/lower FFG values.

DISCUSSION...GOES-E WV shows SW to NE elongated shortwave feature
sliding eastward out of Ohio into increasing/confluent upper-level
flow into the Northeast US.  At the surface a well defined front
and pre-frontal pressure trough exist through the Upper Ohio
Valley though very rich surface to 850mb moisture remains pooled
along the front with CIRA LPW denoting a core of enhanced moisture
across SE OH into west-central WV which generally matches up with
1.9-2" total PWat slug analyzed in the RAP.

CIRA LPW and RAP analysis also shows downstream dry air across the
Cumberland Plateau through south to east-central WV; which
continues to reduce as deeper layer moisture/gradient associated
with the deeper layer frontal zone presses eastward. This allows
for full insolation downstream of the low-level convergence and
given most surface Tds into the mid-70s is resulting in very
unstable environment to work with.  Drier air mixed in, will
likely continue to support forward propagation on stronger cold
pool generation; but along the moisture gradient should allow for
sufficient moisture flux to support 1.5-2"/hr rates.

Duration is likely to be limited to 30-60 minutes; so localized
totals are going to be in the 1-2" range.  Given complex terrain
of the are and recent heavier rains keeping upper levels of the
soils relatively saturated; FFG values of 1-1.5"/hr are within
reach of being exceeded.  Any short-term hang-ups or
short-duration training within the overall convective segments
along the convergence zone are likely the widely scattered
localized enhanced totals at best risk of inducing lower-end flash
flooding concerns.=20=20

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-WJP2H8r8SvHL3jBhG4iPTLfwzwyagwdCig_2AZRv2j0RsmFFUqZuqrGkZxObYgBXQs2=
8scT6DwNB7prkM1l6YtOBrg$  for graphic product...

ATTN...WFO...CTP...ILN...JKL...LWX...PBZ...RLX...RNK...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON   40437898 40207846 39867858 38827949 38187995=20
            37398127 37278253 38078380 38718267 39128170=20
            39588090 40137983=20

=3D =3D =3D
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