Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Jul 16 2025 17:54:53

AWUS01 KWNH 161754
FFGMPD
PAZ000-WVZ000-OHZ000-162353-

Mesoscale Precipitation Discussion 0708
NWS Weather Prediction Center College Park MD
153 PM EDT Wed Jul 16 2025

Areas affected...eastern Ohio, much of Pennsylvania, and a small
part of West Virginia

Concerning...Heavy rainfall...Flash flooding likely

Valid 161753Z - 162353Z

Summary...Scattered thunderstorms should increase in coverage
through the afternoon atop very sensitive local ground conditions
especially in Pennsylvania.  Flash flooding is likely - especially
later this afternoon and into the early evening.

Discussion...Recent radar/satellite imagery depicts a gradual
increase in convective coverage especially across
northern/northeastern Ohio into southwestern Pennsylvania.  The
cells in southwestern Pennsylvania are only loosely organized and
appear to be tied to 1) increased surface heating/destabilization,
2) ascent from a mid-level shortwave trough currently centered
over eastern OH, and 3) confluence on the northeastern extent of a
25kt 850mb jet along the Ohio River. The loose organization of the
cells has led to minimal convective training/repeating that has
largely held rain rates to less than 1 inch/hr in most areas
despite only modest (~15-20 kt) southwesterly steering flow aloft.
 Flash flood potential is relatively isolated in the short term.

Concern exists that with progression through peak heating,
convective coverage will increase while spreading eastward across
the discussion area, leading to cell mergers, modest upscale
growth into clusters, and higher rain rates.  Furthermore, the
higher rain rates are likely to materialize across very sensitive
locales especially across Pennsylvania that have experienced 2+
inches of rain in the past 48 hours.  FFG thresholds are
relatively low - less than 1 inch/hr areawide and near zero in a
few spots.  These factors suggest an eventual increase in flash
flood potential through the afternoon and early evening hours
(extending through 00Z/8p EDT).  Scattered instances of flash
flooding are likely, and significant impacts may occur where
ground conditions are most sensitive.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-ojzJNtbY1_C56SbAVjweHvr11SH6W-z2KSZCpK5QABWjmHLdQ8cda0Rx256gFvlVfeF=
1fuaKY4mOAM210Llmp_9CTo$  for graphic product...

ATTN...WFO...BGM...CLE...CTP...ILN...PBZ...PHI...RLX...

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

LAT...LON   41907773 41617548 40677520 39947554 39777732=20
            39738061 39498237 40258296 41128253 41738078=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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