AWUS01 KWNH 051803

FFGMPD

NJZ000-PAZ000-DEZ000-MDZ000-052102-



Mesoscale Precipitation Discussion 0948

NWS Weather Prediction Center College Park MD

202 PM EDT Wed Aug 05 2026



Areas affected...portions of central/northeast MD into central New

Jersey



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



Valid 051802Z - 052102Z



Summary...Local flash flood risk exists - particularly in

urban/low-lying areas along the I-95 corridor from

Washington/Baltimore through Philadelphia and Trenton.



Discussion...A broken band of shallow convection was drifting

northward at about 10-15 knots across the discussion area and

currently extends from near western sides of Baltimore

east-northeastward to near Philadelphia and Trenton.  The

convection is embedded within an abundantly moist airmass (2.2+

inch PW values), leading to efficient rain rates (subhourly 0.5-1

inch totals) within the convection.  Cells were currently moving

toward urban land surfaces (especially near Philadelphia/Trenton),

which should cause at least isolated excessive runoff issues in

the next 0-2 hours or so.



As this band lifts northward, it'll likely continue intensifying

due to continued surface heating/destabilization in the ambient

environment.  A couple of conditional factors for an increase in

flash flood potential exists, including 1) local backbuilding and

2) any local mesocyclogenesis that may evolve as convection

interacts with a subtle remnant boundary/warm frontal feature in

the region.  Either of these factors could prolong rainfall and

bump rates to 2 inches/hr.  Should this conditional risk

materialize, the combination of rainfall and urban/low-lying areas

would result in an even higher risk of flash flood impacts.



Cook



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



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



ATTN...RFC...RHA...NWC...



LAT...LON   40677521 40437429 40177408 39757460 39297614 

            38987714 39527758 40147700