Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Jul 19 2024 18:05:22

AWUS01 KWNH 191805
FFGMPD
VAZ000-NCZ000-SCZ000-GAZ000-TNZ000-192359-

Mesoscale Precipitation Discussion 0662
NWS Weather Prediction Center College Park MD
204 PM EDT Fri Jul 19 2024

Areas affected...Southern Mid-Atlantic

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

Valid 191804Z - 192359Z

Summary...Showers and thunderstorms are expanding across the
Southern Mid-Atlantic. Slow storm motions around 10 kts combined
with rainfall rates of 2-3"/hr within the most intense cells could
cause some flash flooding this afternoon as storms intensify.

Discussion...Recent Day Cloud Phase RGB and LightningCast data
depict an uptick in glaciating cloud tops and lightning
probabilities along a weak stationary front in the Southern
Mid-Atlantic. This more robust vertical development is likely in
response to filtered insolation ahead of an approaching shortwave
from the west, with little to no CIN across the region. Along the
front, mesoanalysis estimates suggest positive SBCAPE
differentials of 600-1000 J/kg over the last 3 hours, with 2-2.1"
PWATs noted along the front.

As these cells develop this afternoon, weak vertical wind profiles
will ensure storms are quite slow as 850-300 mb mean winds
forecast hover in the 10-15 kt range. This also suggests cells
should remain quite disorganized this afternoon, with new cell
propogation focused along outflow boundaries and the sea-breeze.
Where convection can focus, however, the very moist and
increasingly unstable environment should support some localized
heavy rainfall totals locally around 3-5".

Accordingly, the these totals could easily topple the 1-3 HR FFGs
across the region, which generally hover in the 1-3" range. Aside
from the usual urban sensitivies to the heavy rain, the eastern
Carolinas could be more vulnerable to runoff issues as 2-5" of
rainfall fell over the last 24 hours. By 21Z this afternoon, the
12Z HREF neighborhood probabilities show increasing chances of 1-3
HR FFG exceedence (35-50%), which suggests the threat of isolated
to scattered flash flooding should increase.

Asherman

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!_UMKOcVFKDagHDfUzEFSTsGklRBMiqX4QXIydIoiDkMPULXAoxUE42HnyNEL86QuAKsc=
4rvgugLlIEpjL0J3D0au0vc$  for graphic product...

ATTN...WFO...AKQ...CAE...FFC...GSP...ILM...MHX...MRX...RAH...
RNK...

ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...NWC...

LAT...LON   37158160 37068097 36157921 36777626 36427550=20
            35527561 34757641 34357740 33837957 34038193=20
            34648354 35438375 36768270=20

=3D =3D =3D
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