AWUS01 KWNH 110828
FFGMPD
FLZ000-111428-

Mesoscale Precipitation Discussion 0420
NWS Weather Prediction Center College Park MD
428 AM EDT Tue Jun 11 2024

Areas affected...Southwest Florida

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

Valid 110828Z - 111428Z

Summary...Locally heavy rainfall is expected to develop across
portions of the southwest to west-central Florida Peninsula this
morning. Hourly rain totals 2-3"+ and localized totals between
4-6" will be possible, which may lead to flooding.

Discussion...The deep plume of tropical moisture is advancing
north/northeast early this morning, beginning to overspread the
western and southwestern portions of the Florida Peninsula. The
latest blended TPW products show values above 2.25", which is in
excess of 2 std above normal (near +3 in places). Meanwhile, the
combination of troughing over the Southeast U.S. and a lingering
surface boundary in the area is helping to focus showers and
thunderstorms into the southwest/western FL Peninsula. Current
radar has clusters of storms beginning to organize just offshore
Bradenton and Sarasota, with a slow drift north.

Toward daybreak, the expectation is for more widespread showers
and thunderstorms to develop further to the south/southwest and
move across much of Southwest Florida. This activity will be
focusing into several repeating training bands as the low level
convergence increases and narrows. Expect hourly totals to pick up
with this activity, likely between 2-3" at times based on the 00Z
HREF probabilities (30-50 percent probs). The 6-hr HREF
probabilities have moderate probabilities for at least 5 inches
and even a signal for 8" totals (10-15 percent) through late
morning.

Despite the relative soil dryness and higher flash flood guidance,
the potential intensity of rainfall and total amounts may be
enough to overcome that and result in instances of flooding,
particularly for the more vulnerable and sensitive locations
including urban areas.


Taylor

ATTN...WFO...MFL...TBW...

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

LAT...LON 27478255 27458229 27358210 27138197 26758175
26218146 25868096 25518108 25528137 25988194
26408225 26978259 27258285
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AWUS01 KWNH 041201
FFGMPD
FLZ000-041800-

Mesoscale Precipitation Discussion 0359
NWS Weather Prediction Center College Park MD
800 AM EDT Wed Jun 04 2025

Areas affected...southwestern FL

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

Valid 041200Z - 041800Z

Summary...Showers and thunderstorms are increasing in coverage and
intensity offshore, and should start moving ashore shortly.
Hourly rain amounts to 3" with local amounts to 5" are possible,
which would be problematic in urban areas.

Discussion...An upper level low is noted in water vapor imagery in
the northeast Gulf, south of Apalachicola. An area of scattered
thunderstorms have formed offshore southwest FL which is slowly
broadening and intensifying, while an outflow from overnight
convection is approaching the convection's southeastern flank. As
of this discussion's sending, hourly rain estimates are in the
0.5-1" range to the northwest of Captiva. The synoptic surface
wind field is light out to the east to southeast, while flow at
850 hPa is south to southwest at 20-25 kts per VAD wind profiles
and RAP forecasts, bringing effective bulk shear to 25 kts.
Precipitable water values are around 2". ML CAPE values have been
slowly rising along the immediate coast per SPC mesoanalyses,
where skies are mostly clear as of this discussion's sending. For
the moment, CIN is present inland. Offshore ML CAPE values are
1000-1500 J/kg.

Some additional increase in instability is expected before the
showers and thunderstorms move inland. Should the convection
continue increasing in coverage, which is implied by a modest
increase in the Galvez-Davison index to 30 in the 15-18z time
frame and recent radar trends, this would force the instability
gradient to remain rather coastal. Given the effective bulk
shear, some level of convective organization is anticipated, which
should help with increasing hourly rain amounts if convection gets
anchored to a coastal instability gradient, short periods of cell
training, or cell collisions/mergers occur. The mesoscale
guidance has isolated to widely scattered signals for 3-5" totals
between Sarasota and Naples. Given the ingredients present,
hourly rain amounts to 3" with local totals to 5" are possible,
which would be most problematic in urban areas.

Roth

ATTN...WFO...MFL...TBW...

ATTN...RFC...ALR...NWC...

LAT...LON 28028238 27048159 26028146 25848180 26258210
27838286

$$
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