AWUS01 KWNH 120926
FFGMPD
FLZ000-ALZ000-121525-

Mesoscale Precipitation Discussion 0994
NWS Weather Prediction Center College Park MD
525 AM EDT Thu Sep 12 2024

Areas affected...Southern AL...FL Panhandle

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

Valid 120925Z - 121525Z

SUMMARY...Strong bands of heavy showers and thunderstorms
associated with weakening Tropical Storm Francine will impact
areas of southern AL and especially the FL Panhandle this morning.
High rainfall rates and localized training of storms will likely
result in some areas of flash flooding.

DISCUSSION...The latest GOES-E IR satellite imagery in conjunction
with dual-pol radar shows a couple of stronger bands of heavy
showers and thunderstorms tending to become better organized and
focused across portions of the western FL Panhandle and the
offshore waters of the Gulf of Mexico. This convection is
associated with increasingly convergent and very moist low-level
southerly flow while coinciding with an axis of moderately strong
instability gradually shifting north in connection with a warm
front slowly lifting up across the central and eastern Gulf Coast
region.

MLCAPE values of 1000 to 2000 J/kg are situated very close to the
western FL Panhandle, and this instability coupled with PWs of 2.2
to 2.4+ inches will be supporting extremely heavy rainfall rates
with the stronger and more organized convective cells that
materialize going through the morning hours. Overall, the
low-level flow should become even more convergent over the next
several hours and this coupled with proximity of the
aforementioned front should favor plenty of forcing for multiple
bands of strong convection.

Rainfall rates may reach 2 to 3 inches/hour, and the latest HREF
guidance and HRRR solutions suggest the FL Panhandle should be the
focus for the heaviest rainfall totals with locally as much as 3
to 5 inches of rain possible by late morning. However, the
environment will be conducive for some of these rainbands to train
over the same location, and it's not out of the question that
locally heavier rainfall totals of 6+ inches could materialize.
Heavy rains should also nose northward into parts of southern AL,
but with this region a bit more detached from the axis of greatest
instability, the rainfall totals here are likely to be somewhat
lower.

Some areas of flash flooding will be likely given the high
rainfall rates and concerns for localized training of these bands
of heavier showers and thunderstorms.

Orrison

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

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

LAT...LON 31868716 31738601 31048516 30388476 29838478
29768539 30138605 30218656 30208686 30298720
30538741 31268757
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