123
AWUS01 KWNH 041832
FFGMPD
PAZ000-VAZ000-WVZ000-OHZ000-KYZ000-042300-

Mesoscale Precipitation Discussion 0556
NWS Weather Prediction Center College Park MD
231 PM EDT Thu Jul 04 2024

Areas affected...West Virginia...Portions of Adj. OH, PA, VA, & KY

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

Valid 041830Z - 042300Z

SUMMARY...Strengthening thunderstorms with very deep moisture
crossing complex terrain.  Signs of upstream redevelopment suggest
localized spots of 1.5-3" are possible resulting in widely
scattered and localized possible flash flooding.

DISCUSSION...GOES-E Visible/10.3um EIR and regional RADAR mosaic
has seen a recent strengthening of thunderstorms with a arching
presentation at the lead edge of surge of deeper moisture and
unstable conditions.  EIR temps show numerous bubbling
overshooting tops reaching -70C intermittently.  Given highly
unstable (2000 J/kg of MLCAPE) and highly anomalous moisture (low
to mid 70s Tds) with increased deep layer moisture flux with this
line is resulting in very strong over-turning convective cells.
Given total PWats over 2" (even in elevated terrain), cells will
be capable of 2"/hr rates; though currently strong mid-level
flow/outflow surging has aided by forward propagation limiting
duration and therefore totals to 1-1.5", though in sub-hourly
(15-30 min.) manner.  This alone may trigger some localized flash
flooding given 1hr FFG are in the same general range across much
of the state and into SW PA.

Of further concern, though, is the upstream environment appears to
be recovering fairly quickly with clearing skies and westerly
moist advecting flow.  This suggests additional upstream
redevelopment is probable over the next few hours.  Given the
overall coverage of the initial round and probable scattered
nature with the upcoming round(s), multiple locations may receive
an additional round with a similar 2"/hr rate with sub-hourly
totals in the same 1-1.5" range; resulting in spots of 2-3"
possible through the evening hours, once again at the FFG limit of
1.5-2.5"/3hr, suggesting scattered localized incidents of flash
flooding are possible.

Gallina

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

ATTN...WFO...JKL...MRX...PBZ...RLX...RNK...

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

LAT...LON   40118004 39897960 39407953 38817958 38207992
            37418033 37088080 37018159 37158218 37778256
            38438271 39178248 39698146 39948076