327
AWUS01 KWNH 142106
FFGMPD
PAZ000-MDZ000-WVZ000-OHZ000-150305-

Mesoscale Precipitation Discussion 0439
NWS Weather Prediction Center College Park MD
505 PM EDT Fri Jun 14 2024

Areas affected...Southeast OH...Southwest PA...Northern WV...Far
Western MD

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

Valid 142105Z - 150305Z

SUMMARY...A localized concern for some flash flooding may evolve
over the next few hours from some occasional training of showers
and thunderstorms.

DISCUSSION...A cold front continues to gradually settled southeast
through the OH Valley and will be crossing into the central
Appalachians this evening as a broader upper-level trough arrives
from the Great Lakes region. This front coupled with a weak wave
of low pressure riding along it will facilitate at least a few
broken bands of showers and thunderstorms over the next several
hours for areas of southeast OH, southwest PA, northern WV and far
western MD.

GOES-E visible satellite imagery along with dual-pol radar already
shows the development of some shower and thunderstorm activity,
and an additional expansion and organization of this convection is
expected over the next couple of hours. The latest RAP analysis
shows a moderately unstable airmass with MLCAPE values around 1500
J/kg pooled up along and just ahead of the cold front, and there
are favorable shear parameters with as much as 30 to 40 kts
supporting organized and sustainable updrafts.

Some of the convection is already taking on a somewhat linear
orientation over far northern WV near the southwest PA border, and
the concern at least locally heading into the evening hours will
be some of these convective bands potentially training over the
same area as they advancing gradually into the central
Appalachians.

The PWs are about 1.3 to 1.5 inches, and with the instability and
shear, the rainfall rated with these cells will be capable of
reaching 1.5 inches/hour. Given some considerations for occasional
cell-training, some spotty storm totals of 2 to 3 inches with
isolated heavier amounts will be possible. This will support a
threat for localized instances of flash flooding.

Orrison

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

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

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

LAT...LON   40347953 40347846 39727827 39007900 38998099
            39468275 40158273 40198190 40238094