216
AWUS01 KWNH 251701
FFGMPD
NCZ000-SCZ000-GAZ000-ALZ000-252100-

Mesoscale Precipitation Discussion 1054
NWS Weather Prediction Center College Park MD
101 PM EDT Wed Sep 25 2024

Areas affected...North Georgia

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

Valid 251700Z - 252100Z

SUMMARY...Slow-moving and training thunderstorms associated with
the developing predecessor rain event (PRE) are likely to cause an
urban flash flooding threat as they approach Atlanta.

DISCUSSION...A line of slow-moving and training thunderstorms has
developed west of Atlanta this afternoon. The storms are making
their way into the metro area. The storms have a history of
producing rainfall rates up to 2.5 inches per hour across far
northwestern Georgia.

As the storms move into Atlanta within the next hour, potential
for training as well as locally heavy rain with any stronger storm
cores will likely cause flash flooding in the streams and creeks
around the city that are most prone to flooding due to heavy rain.

Beyond the initial round of heavy rain, backbuilding storms as
well as new development south of town will likely result in a
long-duration rain event where steady light to moderate rain may
continue across the city through the afternoon.

East of town the flash flooding threat through the afternoon will
be significantly lower, as higher FFGs in the rural areas should
mean much more rainfall will be needed before significant flash
flooding occurs. However, given the increasing moisture out ahead
of Helene, slow moving storms, and most importantly, training of
the storms...even outside of town flash flooding will be possible
through the afternoon.

The much greater threat for flooding area-wide is expected to be
later tonight as stronger easterly flow associated with the
approach of Helene slows any eastward-moving storms significantly.

Wegman

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

ATTN...WFO...BMX...FFC...GSP...

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

LAT...LON   35198318 34768295 34408294 33868312 33198372
            33098440 33098481 33028522 33848462 34728366