AWUS01 KWNH 121804
FFGMPD
FLZ000-GAZ000-122200-

Mesoscale Precipitation Discussion 0997
NWS Weather Prediction Center College Park MD
203 PM EDT Thu Sep 12 2024

Areas affected...Near Coastal Southeast GA & Northeast FL...

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

Valid 121800Z - 122200Z

SUMMARY...Short-term tropical warm cloud rates up to 3"/hr across
may result in localized rapid inundation flooding concerns for the
next few hours.

DISCUSSION...Regional RADAR mosaic depicts an outer confluent band
at the far eastern periphery/influence of Francine continues to
transport well above normal low to mid-level higher moisture
values with total TPW over 2.5" with the bulk in the sfc-850mb
layer at over 1-1.1" from the Space Coast toward the mouth of the
St. Johns River.  Through this layer and slightly higher remain
solid with 20-25kts being generally confluent enough to support
deep layer convergence.  The mass piling combined with some
filtered insolation/heating has supported modest instability
(750-1250 J/kg MLCAPE) that is likely to slowly diminish with
time.   Mid-level flow starts to slack in 700-500mb short-wave
ridging across eastern Florida which is supportive of reducing
forward cell motions, but in the near term there is some
northeastward tracking of 5-10kts that is effectively
counteracting the offshore inflow/propagation vectors;
establishing near zero for the cells to allow for the highly
efficient/fluxed moisture and deep warm cloud processes to support
up to 3"/hr rates.=20=20

As the warm conveyor belt convection/height-falls approach from
the west, there will be a short-term enhancement in
convergence/flux before reducing the on-shore flow increasing
vertical shear and tilting limiting depth of stronger updrafts.=20
The onshore flow and frictional convergence may still allow for
further development into the late afternoon, but tilting and
weakening instability to support updraft strength will limit most
intense downdrafts to less than 1-1.5"/hr and likely lower
duration of said showers.  Still spots of 3-4" still remain
possible and may induce localized rapid inundation flooding
especially in urban centers for the next few hours.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7sTxKkEAPnJ_w2hiYjgfu0Rz0uYycAl5cIJd2wB5p9n1kuS-W0-PKBolGIwxHH1XfZ9R=
HYOw4XMMl9i8lrVFKk4sJMc$  for graphic product...

ATTN...WFO...CHS...JAX...

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

LAT...LON   31438165 31418138 31238125 30928134 30488133=20
            30148127 29608109 29688135 30028177 30408199=20
            30928210 31338193=20

=3D =3D =3D
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