827
AWUS01 KWNH 250431
FFGMPD
VAZ000-NCZ000-SCZ000-251029-

Mesoscale Precipitation Discussion 1051
NWS Weather Prediction Center College Park MD
1230 AM EDT Wed Sep 25 2024

Areas affected...much of North Carolina, upstate South Carolina,
and a small part of southern/southeastern Virginia

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

Valid 250429Z - 251029Z

Summary...Continued rounds of thunderstorms are expected to
repeat/train across the discussion area through 08-09Z/4-5am
Eastern.  Rain rates exceeding 2 inches/hour at times are expected
to result in at least localized flash flood concerns.

Discussion...Over the last 2-3 hours, thunderstorms have focused
along an axis extending from far northwestern South Carolina (near
Spartanburg) east-northeastward through Raleigh/Durham and on to
Roanoke Rapids.  These storms were oriented parallel to
west-southwesterly steering flow aloft, allowing for spots of
localized training along the aforementioned axis.  Additionally,
enhanced low-level flow (around 25 knots across the Piedmont) were
aiding in persistent low-level convergence along the axis while
also maintaining 1000-1500 J/kg MLCAPE and 1.5-2 inch PW values
within the pre-convective environment.  These factors are
continuing to support areas of 1-2 inch/hr rain rates at times
that were threatening local FFG thresholds across the region
(generally in the 1.5-2 inch/hr range - lowest in western and
central North Carolina).  This regime is expected to persist, with
at least isolated flash flood potential materializing across the
discussion area.  A few spots of 4 inch rainfall totals are
possible through 10Z.  Some concern exists that the Raleigh/Durham
area could experience heavier rain rates and urbanized flash flood
potential overnight.  Additional concerns exist across areas that
have received 1-3 inch rainfall totals over the past 6 hours,
where wet soils are likely to contribute to a greater risk for
excessive runoff (especially in south-central/southeastern
Virginia and central North Carolina).

Moisture/instability profiles support redevelopment north of the
primary convective axis (across northwestern North
Carolina/southwestern Virginia) as well. Thunderstorms are
expected to be a bit less focused in these areas (with lower
potential for training/repeating).  Isolated instances of flash
flooding are still possible in this regime, however, especially
where 1.5 inch/hr rain rates can materialize over sensitive/low
spots.

Cook

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

ATTN...WFO...AKQ...CAE...GSP...MHX...RAH...RNK...

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

LAT...LON   37467723 36997655 36377659 35677725 35247924
            34898198 35158287 35648240 36178142 36877979
            37317834