AWUS01 KWNH 101531
FFGMPD
GAZ000-ALZ000-MSZ000-LAZ000-102130-

Mesoscale Precipitation Discussion 1172
NWS Weather Prediction Center College Park MD
1030 AM EST Tue Dec 10 2024

Areas affected...Parts of the Deep South and Southeast

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

Valid 101530Z - 102130Z

SUMMARY... Increasing coverage of showers and thunderstorms
through this afternoon will be capable of containing hourly rates
up to 2"/hr and 6-hourly totals over 3", while likely training
over similar areas. This will lead to scattered flash flooding
potential, mainly for urban and low-lying locations

DISCUSSION... Current satellite, radar, and surface observations
display a developing southwest-northeast oriented axis of showers
and thunderstorms extending from eastern LA to central AL. These
showers and thunderstorms are forming in advance of a deep upper
trough (-1.0 to -1.5 standardized anomaly per 00z ECENS)
stretching from the Upper Midwest to the Southern Rockies. This
trough is aiding in strong uniform southwesterly flow advecting
anomalous moisture throughout the column with a source region of
the eastern Pacific, visible via GOES-West ADV LPW. Actual PW
values of 1.5"-1.7" currently spans from eastern LA to central GA,
but these values are forecast to expand throughout the day into
the Southeast in response to strengthening mid and upper level
flow as the the aforementioned trough takes on more of a neutral
tilt over the central U.S.

Radar and GOES-East visible satellite this morning depicts and a
few subtle areas of convergence extending to the northeast of the
approaching cold front. One area impacting Birmingham, AL and a
separate more noticeable axis to the south over Montgomery, AL and
the I-65 to I-85 corridor. These areas of convergence are most
likely to display training storms within the deep uniform
southwesterly flow, with greater instability (500-1000 J/kg)
advecting into the southern line. Overall, CAMs and 06z HREF
guidance display that hourly rates are not expected to exceed 2"
outside of very localized locations, but that 6-hourly totals
could exceed 3" and this would top the 6-hr FFG. So areas
experiencing training thunderstorms will be most at risk for
excessive rainfall as opposed to impacts from individual cells.

Overall, if these amounts are realized it is expected that
scattered low-lying and urbanized locations could experience rapid
water runoff and flash flooding impacts, particularly after 18z
along the I-85 and I-65 corridors of AL.

Snell

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9I0Lt1rnPx9qCAo9zkE6kisJU6T2p8DxE5PKBP-g4294KOZjc8QtecrsXJ5kPF0yaCJM=
NEGcZ5UU0Ls0nhxvVmVupF0$  for graphic product...

ATTN...WFO...BMX...FFC...JAN...LIX...MOB...

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

LAT...LON   34148494 33898413 33208394 32328501 31338706=20
            30698864 30408964 30619019 31059021 31738971=20
            32528879 33258766 33848634=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