749
AWUS01 KWNH 272354
FFGMPD
NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-280352-

Mesoscale Precipitation Discussion 0334
NWS Weather Prediction Center College Park MD
753 PM EDT Mon May 27 2024

Areas affected...Portions of Northern VA...D.C....Central to
Northeast MD...Southeast PA...Northern DE...Southwest NJ

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

Valid 272352Z - 280352Z

SUMMARY...Heavy showers and thunderstorms moving into the
Washington D.C. and Baltimore metropolitan areas over the next
couple of hours will support a threat for some flash flooding.
This may also extend northeast into southeast PA near Philadelphia.

DISCUSSION...Radar imagery shows a band of heavy showers and
thunderstorms organizing across northern VA and through portions
of central and northern MD. The activity over the last 1 to 2
hours has been gradually developing along a subtle convergence
axis in the lee of the Blue Ridge and with the pooling of a
moderately unstable airmass characterized by MLCAPE values of
1500+ J/kg. All of this is also being facilitated by the approach
of a cold front from the west along with a supporting shortwave
trough crossing through the Lower Great Lakes region and central
Appalachians which is providing some large-scale ascent/forcing
for convective organization.

This activity is likely to advance gradually off to the
east-northeast and should impact the I-95 urban corridor from
Washington D.C. through Baltimore and potentially up I-95 into
northeast MD, northern DE and southeast PA including portions of
the Philadelphia metropolitan area over the next few hours.

Some rainfall rates of 1 to 2 inches/hour are expected, with some
isolated 3 inch amounts possible where some brief cell-training
occurs with this band of convection. Given the sensitivities of
the densely populated/urbanized I-95 corridor, some flash flooding
will be possible over the next few hours.

Orrison

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

ATTN...WFO...CTP...LWX...PHI...

ATTN...RFC...MARFC...NWC...

LAT...LON   40387522 40247481 39857491 39357553 38937625
            38667685 38577742 38807769 39117740 39587666
            40087583