Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sat Jul 19 2025 18:12:38

AWUS01 KWNH 191812
FFGMPD
DEZ000-MDZ000-VAZ000-NCZ000-DCZ000-WVZ000-200010-

Mesoscale Precipitation Discussion 0758
NWS Weather Prediction Center College Park MD
211 PM EDT Sat Jul 19 2025

Areas affected...central North Carolina, much of Virginia,
Washington D.C., Maryland, and southern Delaware

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

Valid 191810Z - 200010Z

Summary...Thunderstorms will continue to increase in coverage and
intensity through the afternoon and early evening hours.  Areas of
heavy rainfall are expected across sensitive/urbanized ground
conditions.  Flash flooding is likely through 00Z/8p EDT.

Discussion...Thunderstorms are currently organized in two regimes
- 1) along higher Appalachian terrain in western Virginia and 2)
along a surface boundary from near Raleigh/Durham
east-northeastward in northeastern North Carolina.  Weak westerly
wind fields aloft were supporting slow eastward movement with
ongoing activity (as slow as ~5 mph in North Carolina).=20
Meanwhile, the downstream airmass supporting ongoing convective
activity was abundantly moist and unstable (2+ inch PW values,
2000-3000 J/kg MLCAPE) - all supportive of heavy rainfall with
especially as thunderstorms deepen/intensitfy.  Spots of 1 inch/hr
rain rates have already been estimated per MRMS data, and some of
these rates were falling on relatively low FFGs (0.25-1.5 inch/hr
- lowest across western Virginia and near populated areas near DC
and the Tidewater).

Areas of flash flooding are expected across the discussion area
through 00Z/8p EDT as storms mature.  Over time, storms are
expected to increase in intensity and coverage while spreading
eastward across much of the Mid-Atlantic, eventually reaching the
Chesapeake Bay.  Multicells/clusters and linear segments are all
expected given the weak westerly flow aloft, and several areas of
rain rates exceeding 1.5 inches/hr are expected given the
propensity for storms to 1) move slowly and 2) merge.  Given
sensitive/urbanized ground conditions (with several populated
areas in line for heavy rain activity, including: Raleigh/Durham,
NC; Norfolk, VA; Washington, D.C.), flash flooding could become
significant in several areas later this afternoon.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5FIQO1WQKyqbRzL2qNFwIQmpA_yNuMI0nn8pAXCcVrEJxoEXEgfUmwuXbjbqr-9zfZfR=
z54h7JhJ4UncLRgIfbeegZ0$  for graphic product...

ATTN...WFO...AKQ...GSP...LWX...MHX...PHI...RAH...RNK...

ATTN...RFC...ALR...RHA...TIR...NWC...

LAT...LON   39367740 39257635 38507519 37117577 35937718=20
            35537960 35878082 36548082 37957948 38967846=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.