AWUS01 KWNH 110607
FFGMPD
VAZ000-NCZ000-SCZ000-GAZ000-111205-

Mesoscale Precipitation Discussion 1173
NWS Weather Prediction Center College Park MD
106 AM EST Wed Dec 11 2024

Areas affected...Piedmont to Blue Ridge foothills of GA/SC/NC

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

Valid 110605Z - 111205Z

SUMMARY...There will be some potential for lower end flash or
urban flooding across the Piedmont of GA/SC/NC into the foothills
of the Blue Ridge Mountains through 12Z. Elements of training
rainfall will be capable of producing 1 to 1.5+ in/hr rates with 3
to 6-hour totals of 2-3 inches.

DISCUSSION...0530Z radar imagery across the southeastern U.S.
showed a broad swath of mostly stratiform rainfall extending from
central GA into the Carolinas, though some embedded thunderstorms
were observed within a broken convective line extending from
western GA to the Gulf Coast where MLCAPE was estimated to be
500-1000 J/kg (05Z SPC mesoanalysis). Precipitation was occurring
in advance of a cold front with the convective line along a narrow
axis of pre-frontal convergence near the surface. MRMS rainfall
rates have recently been peaking near 1 in/hr, such as along the
GA/SC border just south of Columbus.

While much of this rain has been beneficial to the region given
below average rainfall over the past few weeks, there will likely
be an uptick in rainfall intensity heading through the morning
hours for locations in the Carolinas. As an upper trough axis,
observed on water vapor imagery just west of the MS River,
continues to advance eastward, continued amplification of the
downstream low level flow will likely result in increased moisture
transport and modest instability increases into the Carolinas
through 12Z. In addition, while instability is not expected to be
a significant contributing factor to enhancing rainfall, a
strengthening upper level jet is likely to enhance lift over the
Blue Ridge and Piedmont later this morning. GOES East DMVs sampled
170 kt near 250 mb over the upper OH Valley at 05Z and some
additional strengthening is likely farther south, ahead of the
through axis becoming neutrally tilted over OK/AR on current water
vapor imagery, forecast to become negatively tilted later this
morning. Increasingly divergent and diffluent flow over the
southeastern U.S. may help to compensate for weak instability and
allow for rainfall rates of 1 to 1.5+ in/hr where heavier cores
train along pre-frontal convergence axes through 12Z. With these
heavier rates, potential for urban flooding or minor flash
flooding will exist with perhaps 2-3 inches of rain in a 3 to 6
hour window of time.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!42KVo-cuWdZA49WyXuK3cBlvwfFLJT3Fo_efugQTMp1x4HlfCgrYm430E7bLCQiYB5kI=
th86gfq61e8Se2dVPOycHJM$  for graphic product...

ATTN...WFO...CAE...FFC...GSP...RAH...RNK...

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

LAT...LON   36627963 35477938 34228065 32668254 32128373=20
            32218460 32788480 34048402 35008291 36418123=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 3.20-Linux