Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon Mar 31 2025 21:56:25

AWUS01 KWNH 312155
FFGMPD
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-010354-

Mesoscale Precipitation Discussion 0102
NWS Weather Prediction Center College Park MD
555 PM EDT Mon Mar 31 2025

Areas affected...Northern Mid-Atlantic and Northeast

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

Valid 312154Z - 010354Z

Summary...Repeating of cells containing hourly rainfall rates of
1.5-2"/hour at times could support a few instances of flash
flooding this afternoon and evening, mainly over urbanized areas.=20


Discussion...Radar and Day Cloud Phase imagery show convective
initiation is well underway over portions of the northern
Mid-Atlantic and Northeast ahead of a lee-side trough and cold
front. Recent mesoanalysis estimates suggest modest MLCAPE values
of 500-1000 J/kg and 35-45 kts of effective bulk shear have
materialized in the pre-frontal airmass to support increasing
organization as this activity matures.

Over the next few hours, expect thunderstorm coverage to continue
expanding along the lee trough, and beneath increasing
right-entrance region forcing overspreading the region. While
individual cell motions will be progressive (40-45 kts), effective
shear vectors oriented parallel to the lee-trough and front will
support repeating of individual cells as the activity grows
upscale. Eventually, this repeating should be interrupted as cold
pools congeal and the activity begins to accelerate eastward
tonight. Before then, however, the repeating nature of these cells
containing rainfall rates upwards of 1.5-2"/hour could lead to a
few instances of flash flooding. Through 3z, HREF neighborhood
probabilities depict a high (40-80%) chance of at least 2" of
rainfall across the highlighted area, with an embedded 25-30%
chance of at least 3" also noted just north of Philadelphia. While
the area has been quite dry as of late, the this output suggests a
few instances of flash flooding could result this afternoon,
especially given the urban footprint of the region.

Asherman

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!8TYDuCfDZBfiekq1vsT_SiVM-YyqKbLPP5cxN4pVFwbXrHsB9SIVAjJwtq8IdauFg6qb=
Y9bhklNHxX5D-wvBR6kCJxU$  for graphic product...

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

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

LAT...LON   41567440 41497377 40877383 40167452 39477524=20
            38217627 38107744 39157779 40327655 40907560=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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