WPC Met Watch

WPC Met Watch


Mesoscale Precipitation Discussion: #0253 (Issued at 809 PM EDT Thu May 09 2024
) MPD Selection


Graphic for MPD #0253

Mesoscale Precipitation Discussion 0253
NWS Weather Prediction Center College Park MD
809 PM EDT Thu May 09 2024

Areas affected...Northern WV...Far Western MD...ExtSouthwest
PA...Ext Southeast OH...

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

Valid 100008Z - 100415Z

SUMMARY...Repeating thunderstorms and upslope moisture flux may
support spots up to 2+" totals in 1-3hrs resulting in possible
localized flash flooding.

DISCUSSION...GOES-E WV depicts an elongated positive tilt trof
across the Great Lakes with a lobe of shortwave energy crossign
through west-central Ohio at this time.  This has supported a few
surface inflections along teh frontal boundary extending across S
PA south of Wheeling, WV to the deeper low SE of ZZV, before
extending further southwest to an inflection just east of
Cincinnati.  Deep layered flow has remained solidly eastward
generally orthogonal to the central Appalachian terrain, though
with the surface wave in proximity, pooled moisture and slightly
backed flow has enhanced surface to boundary layer moisture
convergence to the front across WV.  Deep layer flow ahead of the
surface wave provides an ideal narrow corridor for cell to train
along with very slow southward propagation.  Otherwise, stronger
moisture flux converence into the terrain has sprouted a few
isolated cells in advance.  Good solar heating throughout the day
supported modest unstable air with 1000 J/kg of MLCAPE still
remaining and 1.25" of moisture (mostly in the lowest layers given
upper 50s/lower 60s Tds.  This should support solid moisture
loading into the downdrafts for intense rainfall rates
occasionally reaching 1", but may uptick as wind flow near the
wave increases slightly to the upslope flow.  As such spots of
1.5-2" may occur downstream of the surface wave.  While not
particularly robust, it is through complex terrain and may result
in spotty incidents of flash flooding given FFG values well in the
range for both 1 and 3hr time steps.  Still, coverage and
intensity does not rise to higher probability ans so is only
considered possible through the early overnight period.




LAT...LON   40067854 39807842 39297860 38907904 38677953
            38628050 38818226 39328208 39838091 39977954

Download in GIS format:    Shapefile
 | KML

Last Updated: 809 PM EDT Thu May 09 2024

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