675
FXUS62 KKEY 240355
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
1155 PM EDT Mon Sep 23 2024

...New DISCUSSION, MARINE, AVIATION, TROPICAL SYSTEMS...

.DISCUSSION...
Issued at 1155 PM EDT Mon Sep 23 2024

Earlier this afternoon and continuing into this evening we have
been seeing several quick rounds of showers and a few
thunderstorms pulse across our waters at times. The latest round
that entered the outer Gulf waters is on the downward trend and
looks to be dissipating within the hour. Meanwhile, the outer
Straits of Florida near Cay Sal Bank and points west are seeing
showers pop up once again.

These showers have been the result of the pressure gradient
tightening up between a ridge located across the southeast U.S.
and Potential Tropical Cyclone Nine. This is leading to an
increase in winds which is acting upon the moisture rich boundary
layer. Where speed convergence is greatest is where showers and
thunderstorms have been seen. This is in addition to any previous
outflow boundaries from convection across the southern mainland.
That being said, outside of the aforementioned speed convergence,
there is no large scale subsidence to lead to a more widespread
coverage. With that said, will keep only a modest increase in PoPs
overnight as we expect winds to gradually continue to increase
leading to further convergence opportunities.

Otherwise, as alluded to winds have begun increasing and are
currently seeing 10 to 15 knots across the eastern waters with 15
to 20 knots starting to move into the western waters. Sadly, the
easterly wind is keeping temperatures this hour in the mid 80s
with dew points in the mid 70s. This is maintaining quite muggy
conditions.

&&

.MARINE...
Issued at 1155 PM EDT Mon Sep 23 2024

Small Craft Exercise Caution headlines are in effect for most of
the Florida Keys coastal waters. Moderate to occasionally fresh
easterly breeze has developed this evening and will continue
through the overnight and into Tuesday. This is in response to a
high pressure building along the Eastern Seaboard, and PTC 9 in
the northwestern Caribbean Sea. Heading through the middle and
later part of the week, the forecast will depend on the
development and movement of PTC 9. At this time, we expect fresh
to strong east to southeast breezes to develop late Tuesday, with
strong southeast winds peaking Wednesday night into Thursday as
the tropical system moves northward across the eastern Gulf of
Mexico. The strongest winds and highest seas are expected over
western sections of the Keys waters. Mariners should continue to
closely monitor the latest forecast updates during the next few
days.

&&

.AVIATION...
(00Z TAFS)
Issued at 1155 PM EDT Mon Sep 23 2024

VFR conditions will prevail through the overnight and into Tuesday
morning. Shower coverage should gradually pick up but the timing
for initiation remains uncertain at this time. The most likely
time for the first showers to begin moving into the area should be
around or after dawn. As PTC Nine moves northward through the day
on Tuesday we should see winds increase especially for the EYW
terminal and expecting southeast gusts near 25 knots towards
Tuesday evening. Conditions will gradually deteriorate overnight
Tuesday into Wednesday and Tropical Storm Force winds will most
likely arrive by late Wednesday afternoon or evening for EYW.

&&

.TROPICAL SYSTEMS...
Issued at 1155 PM EDT Mon Sep 23 2024

At 1100 PM EDT, Potential Tropical Cyclone Nine (PTC 9) was
centered about 430 miles south of Key West FL. The system is
moving toward the north-northwest near 6 mph. A northwestward
motion is expected on Tuesday and Tuesday night, followed by a
faster northward to north- northeastward motion on Wednesday and
Thursday. On the forecast track, the center of the system is
forecast to move across the northwestern Caribbean Sea through
Tuesday night, and then over the eastern Gulf of Mexico on
Wednesday and Thursday. PTC 9 is still forecast at this time to
pass west of Key West.

Strengthening is expected during the next few days, and PTC 9 is
forecast to become a hurricane on Wednesday and continue
strengthening on Thursday as it moves across the eastern Gulf of
Mexico.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Tropical Storm Watch for FLZ078.

GM...Tropical Storm Watch for GMZ033>035-044-054-055-074-075.

&&

$$

Public/Marine/Fire...LIW
Aviation/Nowcasts....LIW
Data Acquisition.....DR

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