897
AWUS01 KWNH 140515
FFGMPD
NYZ000-NJZ000-PAZ000-141000-

Mesoscale Precipitation Discussion 0679
NWS Weather Prediction Center College Park MD
114 AM EDT Mon Jul 14 2025

Areas affected...Eastern PA...Southern Upstate NY...Northwest
NJ...

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

Valid 140515Z - 141000Z

SUMMARY...Slowly decaying MCS in proximity to complex terrain
continues to pose flash flooding risk through overnight period.

DISCUSSION...Regional RADAR mosaic depicts a SW to NE convective
line across the Poconos Mtns continuing a slow eastward
advancement, as MCV peels off northeastward into the lower Mohawk
Valley.  While the peak of heating/intensity is likely in the
past, the downstream environment across E PA/Delaware Valley
remains favorable to maintain convective activity with slow
weakening still likely.   RAP, VWP, CIRA LPW analysis notes solid
return moisture channel across the Mid-Atlantic into the Delaware
Valley becoming increasingly confluent with southwesterly warm
conveyor belt out of the Ohio Valley and through the Allegheny
Plateau.  This has brought a very deep, rich moisture environment
with total PWat values of 2-2.2" feeding on 10-15kts of confluent
inflow.  Fluxed air remains unstable and generally uncapped south
of the NY and PA/NJ common border with MLCAPEs of 500-1000 J/kg,
though fingers of elevated MUCAPE to 500 J/kg still remains across
the Hudson River Valley but is more capped and is probable for the
reasoning of the erosion of convective activity toward the north;
while updrafts remain solid strong further south.  IR tops still
cooling through -60C and additional cells southward are likely to
maintain through at least the next few hours even as inflow
continues to weaken.

Given total moisture and vigor to updrafts, moisture flux to the
cells will continue to support rates of 1.5"/hr; occasionally
upticking toward 1.75-2" where some inter-band repeating/training
occurs given cell motion is northeast fairly parallel to the
orientation of the line.  Propagation to the south and southeast
will limit those durations and localized totals of 2-3" remain
possible.  Complex/steep terrain of the Poconos, Catskills and
rugged NW NJ will remain at enhanced risk of excessive runoff and
likely incidents of flash flooding especially early (next 1-3
hours), slowly reducing in magnitude/coverage by 08-10z across far
Southern NY/NE NJ with a much lower probability of reaching the
NYC Metro area by dawn.

Gallina

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

ATTN...WFO...ALY...BGM...CTP...OKX...PHI...

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

LAT...LON   42447436 42217381 41747376 41297403 40967430
            40707458 40417495 40007573 40217652 40657675
            41157657 41887580 42407509