AWUS01 KWNH 061236
FFGMPD
FLZ000-GAZ000-ALZ000-MSZ000-061835-

Mesoscale Precipitation Discussion 0135
NWS Weather Prediction Center College Park MD
836 AM EDT Sun Apr 06 2025

Areas affected...much of central/southern Alabama into western Georgia

Concerning...Heavy rainfall...Flash flooding likely

Valid 061235Z - 061835Z

Summary...A couple of slow-moving MCS continues to produce several
areas of 1-2.5 inch/hr rain rates across west-central Alabama and
far southeastern Mississippi. These trends are expected to
continue eastward across the discussion area, posing isolated to
scattered flash flood potential especially in low-lying and
sensitive areas.

Discussion...A couple of slow-moving linear convective segments
(one from GAD to TCL and another from near MEI to PIB) were
migrating slowly eastward across the discussion area this morning.
The linear segments are oriented largely parallel to fast flow
aloft, with propagation being the primary driver for eastward
movement. Additionally, the pre-convective airmass (characterized
by 1.5+ inch PW values, strong low-level shear, and ~1000 J/kg
MLCAPE) was supporting efficient rainfall processes, with 1-2.5
inch/hr rain rates focused across western AL and southeastern MS
nearer the strongest instability. These rates were approaching
FFG thresholds especially along the BHM/TCL corridor where ~2
inch/hr rain rates and urban land surfaces were resulting in local
peaks in MRMS Flash responses. Higher FFGs south of that area
were resulting in more isolated flash flood potential in the short term.

Over the next 6 hours or so, MCSs should continue eastward
progress across the discussion area, although some slowing of
speed may occur with mid/upper forcing remaining well west of the
area. Surface heating ahead of the MCSs may also provide
opportunity for open-warm-sector initiation that may support more
opportunities for cell mergers through the afternoon hours. The
greatest concern for flash flooding will reside south of I-20 and
north of I-85 (generally from Birmingham to Montgomery to Auburn)
where rain rates are most likely to exceed local FFG through 18Z.

Farther northeast, convection should reach the Atlanta Metro area
and portions of northern Georgia, but storms seem to be outpacing
the northeastward extent of the most unstable air across Alabama.
Isolated flash flooding is possible in this regime as storms reach
Atlanta by around 15Z or so.

Cook

ATTN...WFO...BMX...FFC...HUN...JAN...MOB...TAE...

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

LAT...LON 34458520 34248383 33328378 32418436 31588540
30968719 30858838 32658852 33668756

$$
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)