Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Jul 18 2024 20:25:39

AWUS01 KWNH 182025
FFGMPD
VAZ000-NCZ000-190223-

Mesoscale Precipitation Discussion 0654
NWS Weather Prediction Center College Park MD
424 PM EDT Thu Jul 18 2024

Areas affected...near the eastern border of NC/VA

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

Valid 182023Z - 190223Z

Summary...Thunderstorms with heavy rainfall are moving eastward
near the eastern NC/VA border and broadening in coverage.  Hourly
rain totals to 3" with local amounts to 6" are expected due to
cell training, occasional mesocyclone formation, and cell mergers.

Discussion...A longwave trough across the Great Lakes is pushing a
cold front eastward across the region.  Thunderstorms formed near
the front earlier but have pushed out ahead of the synoptic scale
boundary, driven forward by cold pools.  Precipitable water values
of 2" or so lie here per GPS data and short term RAP forecasts.=20
Effective bulk shear of 30-40 kts lies across the area, leading to
organized convection.  Hourly rain totals thus far per radar
estimates have occasionally peaked in the 2.5-3" range.

While the cold pool appears to be driving the convective forward
to some degree, the trailing end of the outflow is stalling across
central NC, which could lead to renewed heavy rainfall for places
farther west until the synoptic cold front passes by.  The 12z
HREF probabilities of 5"+ in the 18-06z period peak across
northeast NC at 60%, with 8" probabilities as high as 30%.  With
cell coverage increasing, the stage is set for periods of cell
training, cell mergers, and occasional mesocyclones potentially
leading to heavy rainfall.  For now, think hourly totals to 3" and
local amounts to 6" are most likely, but can't rule out higher
amounts in very isolated spots.  Considering recent heavy rainfall
across portions of this area, flash flooding is considered likely
over the next several hours, with the highest impacts in urban
areas.

Roth

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5AnCCaa0SsDEVviMwcRsClM1xdQwvJkgIz-e9wS2-8Ov3hD2aTRZB58cJqfQXHLTRcb9=
8SK0PleRB5k6Iul_pC66KSM$  for graphic product...

ATTN...WFO...AKQ...ILM...MHX...RAH...

ATTN...RFC...MARFC...SERFC...NWC...

LAT...LON   36997598 36347571 35917537 35447536 35167552=20
            34837614 34557654 34507693 34517715 34607763=20
            35107909 35567975 35807991 35937945 36207837=20
            36477782 36747737 36947674=20

=3D =3D =3D
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