AWUS01 KWNH 061326
FFGMPD
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-061925-

Mesoscale Precipitation Discussion 0624
NWS Weather Prediction Center College Park MD
925 AM EDT Mon Jul 06 2026

Areas affected...eastern Pennsylvania, New Jersey, western/central
Maryland, far southern New York State

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

Valid 061325Z - 061925Z

Summary...Isolated flash flood potential is developing this morning...

Discussion...Scattered showers and isolated thunderstorms are
deepening and gradually expanding in coverage across the
discussion area this morning - primarily from near/just north of
Philadelphia east to near New Brunswick. Additional convection was
developing in western/central Maryland near Frederick. The
convection was likely tied to weak isentropic ascent as a subtle
enhancement of 850mb southeasterly flow atop slightly cooler
low-level air was enabling parcels to rise, supporting deepening
convection. Additionally, the overall uptick of convection across
the region is generally suggestive of ascent with weak/subtle
shortwave troughing across the region. Very high PW values (2+
inches) exists in addition to elevated instability (MUCAPE values
500-1000 J/kg) were supporting efficient rainfall processes, and
slow storm motions were already supporting local rain rates of
around 2 inches/hr (per MRMS). Flash flooding is becoming
increasingly likely - particularly as these heavier rain rates
fall over sensitive/urbanized grounds across the discussion area.

The longevity of this risk is uncertain - though CAMs are
suggestive of persistence of this threat through 19Z on at least
an isolated to scattered basis. The isentropic ascent regime will
likely not change much over the next 6 hours, with local 1-2
inch/hr rain rates and overall totals exceeding 4 inches in a few
spots. Given the local sensitivities across the region, locally
significant impacts cannot be ruled out.

Cook

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

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

LAT...LON 40987260 40537274 39977400 39497510 39237670
39217751 39717747 40257686 40777515 40937399

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