104
AWUS01 KWNH 282210
FFGMPD
CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-290409-

Mesoscale Precipitation Discussion 0882
NWS Weather Prediction Center College Park MD
610 PM EDT Tue Jul 28 2026

Areas affected...eastern Pennsylvania, much of New Jersey,
southern New York State

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

Valid 282209Z - 290409Z

Summary...Flash flood potential continues for the northern
Mid-Atlantic into southern New York State.

Discussion...Scattered thunderstorm continue to migrate slowly
eastward/northeastward across the discussion area.  Latest radar
depicts a couple of dominant storm modes: 1) a linear complex
approaching southeastern Pennsylvania extending from near Reading
to near Oxford and Bel Air, MD and 2) more scattered cells and
mergers occurring from Reading northeastward toward New Brunswick,
NJ. The storms remain in a favorable environment for heavy
rainfall, with modest southwesterly steering flow aloft promoting
slow storm motions and nearly 2 inch PW/1500 J/kg MLCAPE promoting
heavy rainfall beneath the storms.  25 kt low-level flow and
ascent aloft from approaching mid-level shortwave troughs also
appear supportive of ongoing convection continuing for another few
hours.

Models/obs all favor slow eastward progression of ongoing
thunderstorm activity.  Areas of 1-2 inch/hr rain rates will occur
on a scattered basis, and local 3 inch/hr amounts are possible on
an isolated basis.  These rates are likely to cause flash flooding
at times in several areas, with particular concern in urban and
flood-sensitive areas from Philadelphia northeastward to New York
City metros and areas near Reading, Allentown, and Easton.  Storms
may reach the eastern parts of the discussion area (eastern NJ and
vicinity) by 03Z/11p eastern or so.

Cook

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

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

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

LAT...LON   41667375 41037270 39777396 39157465 39657565
            39857657 40367652 41057570 41597511