114
FXUS62 KKEY 191843
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
243 PM EDT Wed Jun 19 2024

...New DISCUSSION, MARINE, AVIATION...

.DISCUSSION...
Issued at 230 PM EDT Wed Jun 19 2024
Scattered showers and isolated thunderstorms continue to dot the
Florida Keys island chain as well as the adjacent nearshore and
offshore coastal waters. Surface wind observations suggest the
zone of the greatest confluence was confined to the Lower and
Middle Keys today. Remote sensing- derived rainfall estimates
support this evaluation, general rainfall amounts between
0.1-0.75" across island communities here, with totals generally
less than 0.1" in the Upper Keys. Outside of any passing showers,
skies are generally partly cloudy across the Florida Keys, with
temperatures in the upper 80s to near 90F.

Satellite-derived vorticity analysis shows a well-defined tropical
upper-tropospheric trough (TUTT) cell pinching off in the vicinity
of the Florida Keys. Meanwhile, a tropical wave currently north of
the Lesser Antilles continues to progress towards the west to
northwest. Finally, at the surface, a strong area of high pressure
east of New England continues to interact with newly formed
Tropical Storm Alberto in the Bay of Campeche.

For tonight through Saturday, the aforementioned TUTT cell will
reside in the vicinity of the Florida Keys. Meanwhile, the
tropical wave will approach Northern Florida. These features,
combined with waves of deep moisture originating from the
periphery of a stubborn Central American Gyre near the Yucatan,
will result in well above measurable rain chances. While there
will likely be dry spells mixed in, including one predicted for
much of tonight`s overnight hours by most recent CAM guidance, a
wet and thundery overall pattern appears to be a good bet. It is
tempting to go to elevated thunder chances for some of this period
as well, given the upper-level support for large-scale ascent and
deep moisture evident in forecast soundings, but have elected to punt
for this forecast cycle, given the overall lack of thunder
observed thus far today.

Most ensemble global guidance suggests the aforementioned gyre
will gradually weaken late in the weekend into early next week.
This should gradually lead to a decline in tropical moisture.
Expansive high pressure building across the North Atlantic will
slowly drop measurable rain chances back down closer to normal for
next week, with convection limited to any moisture undulations
pushing in from the gentle southeasterlies.

&&

.MARINE...
Issued at 230 PM EDT Wed Jun 19 2024
A Small Craft Advisory remains in effect for all Florida Keys
marine zones, including the Florida Bay, Bayside and Gulfside,
southeastern Gulf of Mexico, Hawk Channel, and the Straits of
Florida. From synopsis, strong surface high pressure centered off
the New England coast working in tandem with falling pressures
over the Yucatan Peninsula and the Bay of Campeche will result in
moderate to fresh breezes this afternoon through late week. A weak
area of low pressure will begin to develop later this afternoon a
few hundred miles north of the central Bahamas and move towards
the Southeast U.S. coastline. This will lead to slackening east to
southeast breezes for Friday through the weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 230 PM EDT Wed Jun 19 2024
VFR conditions will prevail at both EYW and MTH through the TAF
period. Shower activity will wax and wane so TEMPOs will be included
if impacts to the airport are expected. Near surface winds are
easterly at near 15 knots with gusts at times of up to 25 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  80  88  80  89 /  40  50  50  50
Marathon  80  88  81  89 /  40  50  50  50

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory until 5 AM EDT Thursday for GMZ031>035-
     042>044-052>055-072>075.

&&

$$

Public/Marine/Fire...BT
Aviation/Nowcasts....AP
Data Acquisition.....DR

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