Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue May 13 2025 18:16:37

AWUS01 KWNH 131816
FFGMPD
PAZ000-VAZ000-WVZ000-OHZ000-132245-

Mesoscale Precipitation Discussion 0264
NWS Weather Prediction Center College Park MD
216 PM EDT Tue May 13 2025

Areas affected...western VA into WV and the upper OH Valley

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

Valid 131813Z - 132245Z

SUMMARY...Scattered thunderstorms are expected to expand from
portions of western VA into WV and adjoining areas of southeastern
OH and southwestern PA through 23Z. Hourly rates within the
afternoon storms are expected to exceed 1 in/hr at times due to
short term training.

DISCUSSION...Visible satellite and radar imagery at 18Z showed a
region of scattered thunderstorms from central WV into western VA
near I-64. These storms were located ahead of a shortwave trough
moving north from northeastern TN into western NC, part of a
larger closed mid-level low centered over KY/TN. The region was
also situated southwest of a broad region of overcast skies where
daytime heating has combined with modest moisture to support
instability. The environment near this region of thunderstorms
contained 500-1500 J/kg MLCAPE with weakly anomalous precipitable
water values with low level flow from the southeast at 10-20 kt
over western VA, but with weaker magnitudes over central WV.

The main concern for flash flooding is due to the expectation of
additional convective development ahead of the shortwave trough
within clear skies (unstable environment). While a general
movement of thunderstorms toward the north or east is expected,
unidirectional flow from the south to south-southeast will be
supportive of short-term training axis of heavy rain, capable of
generating hourly rainfall 1 to 1.5 inches (perhaps locally higher
but likely staying below 2 inches). These instances are expected
to be isolated to widely scattered but would be in excess of
hourly flash flood guidance which is near 1 inch per hour over
this region of the central Appalachians.

Otto

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7Xuvk6gN6MMtXSPXK19CH4hYN-I5VIhYLOF-9Y2RSoZJcD9jWzZFCTQTVz99Ictmjf6k=
D9G4Fcmweo-KYuh8W02YUYg$  for graphic product...

ATTN...WFO...LWX...PBZ...RLX...RNK...

ATTN...RFC...MARFC...OHRFC...SERFC...NWC...

LAT...LON   40138083 39918020 39127989 38357957 37727941=20
            37317987 37158134 37458181 38178224 38758226=20
            39318201 39728164 40038123=20

=3D =3D =3D
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