AWUS01 KWNH 131857
FFGMPD
FLZ000-132230-

Mesoscale Precipitation Discussion 1004
NWS Weather Prediction Center College Park MD
257 PM EDT Fri Sep 13 2024

Areas affected...FL Panhandle

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

Valid 131856Z - 132230Z

SUMMARY...A convective line segment moving across the FL Panhandle
may continue to produce localized areas of flash flooding at it
moves east through 22Z. High rainfall rates of ~1 inch in 15
minutes and a quick 2-4 inches will be possible.

DISCUSSION...KEVX radar imagery from 1830Z showed a small, forward
propagating line of thunderstorms extending from Washington
County, FL into the northern Gulf of Mexico. This line has been
responsible for MRMS estimated rainfall of 2-4 inches from
Choctawhatchee Bay to the I-10 corridor and observed rainfall
rates near 1 inch in 15 minutes per the Wunderground/Wundermap
rainfall network. The line is located along the leading edge of
dry air seen on water vapor imagery pushing east across AL and the
western FL Panhandle, embedded in 1000-1500 J/kg MLCAPE and
precipitable water values of 2.1 to 2.4 inches per the 18Z SPC
mesoanalysis.

While recent radar trends have shown a tendency for the convective
line to forward propagate just south of I-10, there has also been
recent convective strengthening just offshore with line
orientation matching the mean steering flow, supporting localized
training. A continued eastward progression of convection is
expected over the next 2-4 hours but brief instances of training
are likely, especially to the south of a subtle west-east boundary
observed on visible imagery extending westward from TLH.
Antecedent rainfall near and north of Apalachicola has exceeded 6
inches over the past 48 hours which will allow for reduced
infiltration capacity of additional heavy rainfall. Given the high
short term rain rates of 1-2 inches in 15 to 30 minutes, localized
flash flooding will continue to be possible for the next 2-4 hours.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7gDSIgE0E_taRp2I7xWcgG7yRPt1LKG0-wuLo1UQc3cHGMxVZu7Qov6AKYu9spD-a2QC=
3jaAy0RP8dnhlmpBpuC6j5A$  for graphic product...

ATTN...WFO...TAE...

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

LAT...LON   30738525 30598439 30458386 30178378 29868392=20
            29598420 29268494 29668634 30238620 30418606=20
            30468593 30728566=20

=3D =3D =3D
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