AWUS01 KWNH 090921
FFGMPD
FLZ000-GAZ000-ALZ000-091520-

Mesoscale Precipitation Discussion 0053
NWS Weather Prediction Center College Park MD
520 AM EDT Sun Mar 09 2025

Areas affected...Far Southern GA...FL Panhandle into Northern FL

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

Valid 090920Z - 091520Z

SUMMARY...Locally training clusters of heavy showers and
thunderstorms this morning may result in isolated areas of flash flooding.

DISCUSSION...The latest GOES-E IR satellite imagery along with
dual-pol radar shows clusters of heavy showers and thunderstorms
gradually expanding in coverage across portions of the central and
eastern Gulf Coast region as southerly warm air advection and
moisture transport interacts with a quasi-stationary front
extending east from a wave of low pressure just east of New
Orleans, LA. A modest low-level jet of 20 to 30+ kts is focused
out ahead of this low pressure wave, with the primary nose of this
situated up into the FL Panhandle region where PWs are gradually
increasing along with instability.

MIMIC-PW data shows the pooling of 1.5 to 1.75 inch PWs currently
near the central Gulf Coast with the latest RAP analysis showing
MUCAPE values of 500 to 1000+ J/kg. However, the 3-hour MUCAPE
differentials are on the order of +400 to +600 J/kg across far
southern AL through the western part of the FL Panhandle and this
is where some of the more organized clusters of convection have
been developing over the last couple of hours.

As a positively-tilted mid-level trough and associated closed low
continues to eject east out of the southern Plains and toward the
Lower MS Valley this morning, there will be a gradual increase in
downstream upper-level divergence along with a corresponding
subtle increase in the low-level jet. This coupled with proximity
of the front across especially the FL Panhandle vicinity should
help facilitate a further expansion and organization of convection
in a general west to east fashion which will bring a concerns for
locally training showers and thunderstorms.

The HRRR has been generally trending wetter over its last few
model runs, and the HRRR coupled with the 00Z NSSL-MPAS guidance
support rainfall rates of 1 to 2 inches/hour, with sufficient
levels of cell-training to generate totals of as much as 3 to 5
inches by late this morning. These rains will be falling over
areas that are relatively dry based off the latest NASA SPoRT soil
moisture data, but given some of the wetter model trends overnight
along with the latest radar and satellite data, it will be
possible that enough rain falls this morning for some isolated
areas of flash flooding.

Orrison

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

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

LAT...LON 31198337 31148199 30858134 30458130 30138148
30008205 29898300 29848401 29668506 29908550
30268609 30308699 30608721 30878690 31038587
31088475
$$
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