764
AWUS01 KWNH 052017
FFGMPD
VAZ000-NCZ000-WVZ000-SCZ000-TNZ000-060000-

Mesoscale Precipitation Discussion 0566
NWS Weather Prediction Center College Park MD
416 PM EDT Fri Jul 05 2024

Areas affected...Western Virginia and North Carolina

Concerning...Heavy rainfall...Flash flooding likely

Valid 052016Z - 060000Z

SUMMARY...Flash flooding is likely as pre-frontal and slow-moving
storms produce rates to 3 inches per hour. Isolated instances of
significant flash flooding are possible.

DISCUSSION...Pre-frontal convection that has developed across the
Piedmont of Virginia and North Carolina has been producing
rainfall rates to 3 inches per hour over the areas they have been
forming. The storms that have formed over the mountain communities
of NC have a history of causing street flooding in poor drainage
areas. PWATs are up around 2 inches in the area, indicating an air
mass with plentiful moisture. The atmosphere is uncapped, with
CAPE values up to 2,000 J/kg in place. Given the local
sensitivities to flash flooding, these parameters, while far from
off-the-charts, have been enough to produce flooding producing
rainfall. With little in the path of these storms that would
suggest meaningful weakening of the storms as they progress
eastward into the Piedmont, expect continued widely scattered
instances of flash flooding with isolated significant flash
flooding possible.

CAMs guidance has been very poor with the convective evolution so
far. Much of the guidance, if there is convection at all, shows it
as a line that quickly crosses the area with only isolated
convection out ahead of the main line. However, the evolution of
the convection so far has been much more widespread, indicating
much better ability for the storms to develop and produce heavy
rainfall. Thus, much of the guidance has been discounted, in favor
of a continuity approach into the evening suggesting continued
convective development out ahead of the line. The front has been a
clear demarcation of the ending of any significant rainfall, and
expect that to continue to be the case as well.

Wegman

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

ATTN...WFO...AKQ...CAE...GSP...LWX...MRX...RAH...RLX...RNK...

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

LAT...LON   38997922 38457851 37517858 36487883 35447970
            34848093 34998251 35738239 36878155 38198078
            38578009