042
AWUS01 KWNH 291702
FFGMPD
GAZ000-TNZ000-ALZ000-MSZ000-292200-

Mesoscale Precipitation Discussion 0550
NWS Weather Prediction Center College Park MD
102 PM EDT Sun Jun 29 2025

Areas affected...Middle TN...Northern AL...Northwest
GA...West-central MS...

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

Valid 291700Z - 292200Z

SUMMARY...Stronger than normal pulse thunderstorms within deep
moisture, slow flow environment may support scattered to numerous
cells with capability of 2" totals in 30-60 minutes.  Incidents of
localized flash flooding is considered possible.

DISCUSSION...GOES-E WV suite once again shows closed TUTT cell
over E GA just west of Augusta with northwest quadrant of enhanced
moisture within/along NNE to SSW jet streak across Middle TN
becoming more diffluent along and south of the TN River Valley.
Clear skies and stagnant humid low level moisture have supported
rapid increase in broad area of 2000-2500 J/kg of MLCAPE across
much of northern and central AL, with extensions into west-central
MS and western GA.  Deep layer moisture is over 2".  Differential
heating along old cirrus canopy from the western portion of Middle
TN into central MS has result in weak thermal circulation to
support weak, yet sufficient convergence in this highly unstable
environment for broader ascent with scattered to numerous coverage
noted.

Deep layer steering is very weak at 5-10kts and also a tad
diffluent toward the south and southeast.  So with stronger
vertical moisture flux/loading to the updrafts, warm cloud depths
over 13-14Kft will support up to 2" totals within 30-60 minutes.
Limited dry air aloft will support moist outflow boundaries and
convergence will support newer activity with each cycle
potentially increasing the areal expanse of the updrafts resulting
in a broader area of intense rainfall. Given the shear
rate/magnitude...rapid inundation and runoff would be normally
expected but lower FFG due to an above normal season may further
limit infiltration and increase runoff.  As such, highly
focused/localized flash flooding may be possible in/near the cores
and around urban centers such as Huntsville, Birmingham, Nashville
or Atlanta.

Gallina

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

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

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

LAT...LON   36428678 36388549 35468504 34298461 33608397
            32808432 32558518 32618608 32498743 32398887
            33248920 33708820 34948777 35848747