282
AWUS01 KWNH 262115
FFGMPD
PAZ000-MDZ000-VAZ000-NCZ000-WVZ000-OHZ000-TNZ000-KYZ000-270113-

Mesoscale Precipitation Discussion 0330
NWS Weather Prediction Center College Park MD
514 PM EDT Sun May 26 2024

Areas affected...PortIons of the Upper OH Valley and the Central
Appalachians

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

Valid 262113Z - 270113Z

SUMMARY...A long-lived QLCS with heavy showers and thunderstorms
will be crossing through portions of the upper OH Valley and the
central Appalachians over the next few hours. Given locally wet
antecedent conditions, the rainfall may be enough to cause some
instances of flash flooding.

DISCUSSION...The latest satellite and radar imagery shows a
long-lived and severe QLCS advancing quickly east through portions
of the upper OH Valley, and this will be reaching into portions of
the central Appalachians over the next couple of hours. The
downstream thermodynamic environment across the central
Appalachians is moderately unstable with MLCAPE values as high as
1000 to 1500 K/kg across areas of eastern OH/southwest PA and much
of WV. However, a stronger pool of instability is noted farther
south over eastern TN involving the broader Cumberland Plateau
region where some MLCAPE values are as high as 2000 to 3000 J/kg.

Rainfall rates with the storms are likely to be highest over areas
of eastern TN and far western NC where the greatest instability
and concerns for more discrete cell-development ahead of the
remaining QLCS will occur over the next few hours. Rainfall rates
here will likely approach or exceed 2"/hour, with some spotty 3 to
4 inch totals possible.

Farther north across much of WV and into eastern OH and especially
southwest PA, the progressive nature of the QLCS will limit
overall storm totals to 1 to 2 inches, but there may be some
rainfall rates of up to 1 inch in as little as 30 minutes as the
initial convective line arrives. The activity should tend to
maintain some convective vigor given the downstream instability
environment, and areas even east of the Appalachians may see
convection survive heading later into the evening hours.

Large areas of the central Appalachians in general are rather
moist, and portions of northern WV, southeast OH and southwest PA
saw heavy rains last evening and overnight which have resulted in
elevated streamflows. Given this and the locally rugged terrain
helping to enhance runoff further, some localized areas of flash
flooding will be possible over the next few hours.

Orrison

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

ATTN...WFO...CLE...CTP...GSP...JKL...LWX...MRX...OHX...PBZ...
RLX...RNK...

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

LAT...LON   41288003 40937901 39867845 38117909 36388086
            35688230 35408386 35958475 36838369 37908226
            39298163 40338167 41128093