Mesoscale Precipitation Discussion 0358
NWS Weather Prediction Center College Park MD
820 PM EDT Sat Jun 19 2021

Areas affected...Portions of Eastern Mississippi and Northern
Alabama into Northern and Central Georgia

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

Valid 200019Z - 200519Z

Summary...Training of convective bands associated with Tropical
Depression Claudette will maintain a flash flood threat across
portions of interior Southeast this evening.

Discussion...At 00Z, spiral bands associated with the circulation
of slow-moving Tropical Depression Claudette continue to exhibit
cell training across much of the outlook area. Within the eastern
flank from eastern Alabama into central and northern Georgia,
robust southerly inflow within the lower layers (40+ kts at 850
mb) continues to lead to strong moisture transport and
theta-e/PWAT advection, as 850 mb moisture flux anomalies continue
to exceed 5 standard deviations above normal. Given the strength
of the low-level inflow relative to the mean 850-300 mb mean flow
(becoming more parallel while exceeding the mean wind speed),
north-south oriented Corfidi Vectors will maintain upwind
propagation and thus a continued high probability of additional
training within the south-north bands east of TD Claudette's
center.

Across northern Alabama into northern Georgia, where the strong
low-level inflow is more easterly, strong upwind propagation is
also noted with the westerly Corfidi Vectors. Thus expect another
more prolific area of cell training along the northern-northwest
periphery of TD Claudette. Therefore, despite the relative lack of
deep-layer instability (MUCAPEs ~500-1000 j/kg per the latest SPC
mesoanalysis), the otherwise highly favorable thermodynamical and
dynamical factors will favor areas of 2+ inch/hr rainfall rates,
especially toward the slowly-rotating comma head.

Much of the mesoscale guidance (CAMs) show pockets of 3-5+ inches
within the outlook area through 05Z, with the more concentrated
area along the northern and northeastern periphery of TD
Claudette's circulation. The flash flood risk will be especially
heightened across portions of eastern Mississippi and central
Alabama, where the antecedent conditions (lower FFG values) will
be more conducive to additional short-term runoff issues. 

Hurley

ATTN...WFO...BMX...FFC...GSP...HUN...JAN...

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

LAT...LON   34928439 34748350 34088290 33298279 32488328
            32158430 32678577 32778663 32388769 32298879
            32698906 33258875 34298731 34828567