729
AWUS01 KWNH 132053
FFGMPD
NYZ000-PAZ000-MDZ000-WVZ000-OHZ000-140200-

Mesoscale Precipitation Discussion 1275
NWS Weather Prediction Center College Park MD
452 PM EDT Sun Sep 13 2026

Areas affected...Central and Eastern OH...Far Northern
WV...Western and Northern PA...Western and Southern NY

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

Valid 132052Z - 140200Z

SUMMARY...Scattered showers and thunderstorms will be expanding in
coverage over the next couple of hours across portions of the
Upper OH Valley through the Lower Great Lakes region and some
portions of the central Appalachians. Locally heavy rainfall rates
and wet/saturated antecedent conditions will support a concern
this evening for isolated areas of flash flooding.

DISCUSSION...The latest GOES-E visible satellite imagery along
with radar data shows scattered areas of showers and thunderstorms
developing and expanding in coverage across portions of central
and eastern OH through northwest PA and into western NY.

This activity is developing along and ahead of a cold front that
is bumping up against a moist and unstable airmass characterized
by MLCAPE values of 1000 to 2000 J/kg and PWs locally as high as
1.5 inches. Some relatively strong shear is in place over the
region with as much as 40 to 50 kts of effective bulk shear, and
this will support some storm organization over the next few hours
as late-afternoon heating/instability persists ahead of the cold
front.

Gradually this activity will advance off to the east, with the
activity eventually becoming more prevalent across eastern OH
through northwest PA and southwest NY where instability is rather
well established. The environment is conducive for some rainfall
rates of up to 1.5 inches/hour, and some hires model CAMs suggest
a threat through this evening of spotty 2 to 3 inch rainfall
totals where some localized cell-training sets up. This is
suggested with the orientation of the deeper layer steering flow
relative to the current convection, so some of these highly
localized heavier totals seems plausible.

Given the wet and locally saturated soil conditions and already
elevated streamflows across the region from recent rainfall, these
additional rains this evening may support at least an isolated
threat for flash flooding.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...ALY...BGM...BUF...CLE...CTP...ILN...PBZ...RLX...

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

LAT...LON   43717562 43707441 43147376 42107446 41687498
            41377601 41047723 40217865 39168024 38868271
            39218381 39748421 40118389 40918272 41298162
            41808004 42417929 43077863 43367751 43507672