859
AWUS01 KWNH 092159
FFGMPD
GAZ000-TNZ000-ALZ000-MSZ000-100330-

Mesoscale Precipitation Discussion 0990
NWS Weather Prediction Center College Park MD
557 PM EDT Sun Aug 09 2026

Areas affected...Mid-South

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

Valid 092157Z - 100330Z

SUMMARY...Heavy showers and thunderstorms will continue this
evening across portions of the Mid-South which will maintain a
concern for additional pockets of flash flooding.

DISCUSSION...Multiple clusters of relatively slow-moving showers
and thunderstorms are seen impacting areas of central to northwest
AL and also adjacent areas of northeast MS and middle TN.

There are still areas of northern AL and parts of middle TN that
have a substantial pool of boundary layer instability in place
with MLCAPE values of around 2500 J/kg. Meanwhile, outflow
boundaries are seen slowly advancing out from the existing areas
of convection across the region.

Over the next few hours, some outflow boundary collisions are
expected which will drive a threat for expanding and regenerating
clusters of convection over the region. Northern AL in particular
appears to be at risk for seeing the best potential for this based
on the latest GOES-E visible satellite imagery trends.

Given the instability and high PW environment, with PWs of 2.0 to
2.2 inches, the rainfall rate potential will be very high and
capable of reaching 2 to 3 inches/hour. Slow cell-motions and
potential for a few cell-mergers may allow for some spotty 3 to 4
inch rainfall amounts going through this evening.

Already there have been a couple of flash flood warnings that have
come out across central and northwest AL, and some additional
flash flooding concerns will exist going into the evening hours as
the convective threat continues.

Orrison

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

ATTN...WFO...BMX...FFC...HUN...JAN...MEG...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON   35638690 35618629 35378566 34778551 34168589
            33288675 32908765 32978853 33408879 34308822
            35238781