AWUS01 KWNH 022310
FFGMPD
FLZ000-GAZ000-ALZ000-030500-

Mesoscale Precipitation Discussion 0854
NWS Weather Prediction Center College Park MD
709 PM EDT Sat Aug 02 2025

Areas affected...Southern AL...Southern GA...Northern Florida...

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

Valid 022310Z - 030500Z

SUMMARY...Risk for widely scattered flash flooding continues for a
few more hours as slow, highly efficient thunderstorms seek out
remaining instability pockets along the deep layer frontal zone.

DISCUSSION...Surface observations and RAP analysis suggests deep
layer frontal zone remains stationary across southern GA back into
S AL but has become harder to delineate as initial round of
thunderstorms has resulted in larger scale over-turning.  Outflow
from the initial convection has increased moisture convergence
along the southern edge of the older convective debris across
southern GA providing sufficient directional and modest speed
convergence to trigger additional thunderstorm development.  Air
temps remain in the low 90s with ample deep layer moisture, Td in
the mid 70s with core of CIRA LPW (Sfc-850mb) along the northern
Florida boarder with AL/GA with values over 1". Given 850-500
moisture axis resides generally in the same vicinity (if a tad
north), overall moisture remains in the 2.25-2.5" total PWat
range.  Given deep warm cloud layers (14-16Kft) and solid updraft
vigor (given 2000-2500 J/kg of MLCAPE); efficient warm cloud
processes will keep the potential of 2-3"/hr rates (higher in
shorter time frames). 

However, unlike earlier this afternoon, convective clusters have
formed along the southern interface/outflow boundary and reside in
deeper fairly unidirectional, if weak steering flow to allow for
some potential training/repeating over the next few hours before
instability is exhausted or slowly diminishing after sunset.  Some
southerly surface to boundary layer flow may allow for some
recharge of unstable air prior to the arrival of the next cluster.
 As such, spots of 3-5" totals will remain possible through the
early overnight period (though bulk of heaviest rates/totals
should be over the next few hours).

Hydrologically, sandier soils are likely to uptake much of the
heavy rainfall but the shear rates of 2.5-3"/hr are likely still
too much even for best infiltration and 3-6hr totals locally of
3-5" are also at the edge of FFG exceedance and as such, localized
flash flooding will remain possible and, of course more likely
near larger urban centers. 

Gallina

ATTN...WFO...BMX...JAX...MOB...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON   32128764 31848490 31568263 31198145 30718136 
            30048126 29898187 30138333 30398455 30608543 
            30908728 31248802 

$$
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