Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Sep 25 2024 18:00:38

AWUS01 KWNH 251800
FFGMPD
GAZ000-ALZ000-252359-

Mesoscale Precipitation Discussion 1055
NWS Weather Prediction Center College Park MD
200 PM EDT Wed Sep 25 2024

Areas affected...Southern Alabama into Western Georgia

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

Valid 251759Z - 252359Z

SUMMARY...Slow-moving bands of heavy thunderstorms in a plume of
tropical moisture ahead of Helene will continue to produce areas
of 2.5" hourly rainfall and the potential for 4" rest of the
afternoon.

DISCUSSION...Clusters of slow-moving heavy thunderstorm bands
oriented SSW to NNE over southern/eastern AL will continue to
converge and shift north over the next hour or so, then likely
drift east into western Georgia rest of the afternoon. Hourly
rainfall of 2.5"/hr has been estimated from both KMXX and KEOX
over Butler Co AL. While 1hr FFG exceeds 3" there, lower FFG near
2"/hr is in the Montgomery metro area as points east where an inch
of rain fell overnight.

This activity is on leading edge of the core of Helene-sourced
moisture with PW of 2" just now entering southeast AL. A tongue of
2.25" PW will shift up the AL/GA border by 00Z on 15 to 20kt
southerly flow, further increasing the risk for extreme rainfall
trough tonight.

Guidance has generally underdone the coverage of activity though
recent HRRRs are decent. Through 00Z, areas of 2-4" are likely.
However, this area has been in drought, so FFG will only be
exceeded in the most extreme rates and potentially in more
sensitive urban areas like Montgomery, so flash flooding through
the afternoon is considered possible.

This event alone is the drought breaker for much of southeast AL,
but unfortunately this area will continue to receive extreme
rainfall at times now through the passage of Helene Thursday
night. Further updates on this situation can be expected this
evening and Helene in general at hurricanes dot gov.

Jackson

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!4_E-pL511Oj2rc_woMysisJ7HgYCBVuJG5hJFlHVjDgcdZxF6aBRhbZ9eawPpWCoesqE=
6PidKCjNULmwP9J4_jcF71Q$  for graphic product...

ATTN...WFO...BMX...FFC...MOB...TAE...

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

LAT...LON   33218473 33008406 32188449 31058522 31028696=20
            32408663 33038619=20

=3D =3D =3D
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