Mesoscale Precipitation Discussion 0594
NWS Weather Prediction Center College Park MD
559 PM EDT Fri Aug 03 2018

Areas affected...Wrn VA...Ern WV...Wrn MD...S-cntrl to Nern
PA...Upstate NY

Concerning...Heavy rainfall...Flash flooding POSSIBLE

Valid 032200Z - 040400Z

Summary...Heavy rainfall threat is expected to continue through
the evening hours.  Additional flooding concerns are possible.

Discussion...Model soundings from recent runs of the HRRR continue
to show high RH values through the low and mid levels, with tall
skinny CAPEs - supporting efficient rainfall processes.  The
persistence of deep unidirectional flow, high PWs and the
larger-scale lift afforded by shortwave energy lifting along the
leading edge of the trough, will continue to support rounds of
training precipitation, resulting in additional heavy amounts
across the region.  Several hi-res model runs show additional
locally heavy amounts continuing into the evening hours, with the
18 UTC HREF Mean neighborhood probabilities indicating a
significant chance for additional amounts of 1-2 inches, with
locally heavier accumulations, within the highlighted region. 
Three-hour flash flood guidance values are an inch or less within
a large portion of the highlighted region - suggesting any
additional heavy amounts would likely cause hyrdrologic concerns. 
Consensus of the hi-res guidance shows the heavy rainfall threat
subsiding from south to north as the shortwave trough and better
forcing begins to lift out overnight.

Pereira    

ATTN...WFO...AKQ...ALY...BGM...CTP...LWX...PBZ...PHI...RLX...
RNK...

ATTN...RFC...MARFC...NERFC...OHRFC...SERFC...

LAT...LON   42207530 41927424 40157630 39237755 37707836
            36837878 36577930 36747969 37967983 38897959
            39347902 40527798 41357700