AWUS01 KWNH 082012
FFGMPD
PAZ000-MDZ000-VAZ000-NCZ000-WVZ000-090145-

Mesoscale Precipitation Discussion 0645
NWS Weather Prediction Center College Park MD
411 PM EDT Wed Jul 08 2026

Areas affected...portions of the central Appalachians into the
VA/NC Piedmont

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

Valid 082010Z - 090145Z

Summary...A few isolated to widely scattered instances of flash
flooding will be possible across the central Appalachians into the
Piedmont of VA/NC through early evening. High hourly and
sub-hourly rainfall rates of 1-2 inches are expected.

Discussion...20Z visible satellite and radar imagery showed
scattered thunderstorms over southern WV into portions of western
VA, along with a small group of thunderstorms over the Alleghenies
of southern PA. The storms were located within an anomalous
moisture plume, located in the vicinity of a quasi-stationary
front draped from the Mid-Atlantic into eastern and northern WV.
20Z SPC mesoanalysis data showed MLCAPE ranged from 1000-2000 J/kg
and GPS PWs ranged from 1.5 to 1.9 inches across the region, or
within the 90th to 95th percentile for early July.

Mean flow through the LFC-EL layer and low level flow is generally
from the west, but weak. The westerly winds should keep a general
west to east motion for most cells and a lack of better shear
should keep cells disorganized and short-lived in nature. However,
terrain and outflow interactions could support brief backbuilding
and a few slower moving cells, capable of 1 to 2 inches in an hour
or less. In fact, 15-minute rainfall over 1 inch has already been
observed through MRMS-estimates and the potential for 2+ inches of
rain in an hour may occur on an isolated basis. Given portions of
the region have fairly low FFG values of less than 2 inches in 3
hours, and the potential for isolated 2 to 4 inch totals, isolated
to widely scattered flash flooding will be possible through the
early evening hours. Beyond sunset, cells should begin to
dissipate with the loss of daytime heating.

Otto

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

ATTN...WFO...AKQ...CTP...GSP...LWX...PBZ...RAH...RLX...RNK...

ATTN...RFC...ALR...ORN...RHA...TIR...NWC...

LAT...LON   40607828 40407806 40097791 38907823 37247855 
            36307909 35778018 35778108 36288161 37408125 
            38418049 40257920 40597882