Area Forecast Discussion
Issued by NWS Key West, FL

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110
FXUS62 KKEY 170820
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
420 AM EDT Fri Oct 17 2025

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

.KEY MESSAGES...

-Low level moisture returns briefly today with slightly higher
 rain chances.

-Bouts of breezy conditions will commence today, lasting through
 the early part of the weekend. Small Craft Exercise Caution
 headlines are necessary for the Florida Keys coastal waters.

-A Small Craft Advisory may be required for portions of the
 weekend.

-A Coastal Flood Statement is in effect for all of the Florida
 Keys island communities.

&&

.DISCUSSION...
Issued at 423 AM EDT Fri Oct 17 2025
Thick low altitude cloud cover and clusters of showers across the
Florida Keys coastal waters indicate the atmosphere is slightly
more active than yesterday. GOES East satellite observations show
stratocumulus lingering over the Straits and the Outer Gulf.
However, despite the low level moisture, CIMSS Precipitable Water
scans measured an environmental PWAT around 1 inch. Deep layers of
sinking air remain over South Florida, as was seen in the 00Z
KKEY sounding. This subsidence is expected to remain for the rest
of the day.

The most notable change across the Keys today will be the winds. A
high pressure system over the eastern CONUS is sinking south
towards the Florida peninsula and tightening the pressure
gradient. Breezes along the reef were gentle to moderate after
midnight, though Carysfort Reef measured moderate to fresh
breezes before sunrise. This is consistent with an expected wind
surge, forecast to arrive in the Keys later today. Small Craft
Advisories may be required tonight.

.FORECAST...
After the wind surge moves across the Florida Keys, the
environment will be dry for the first half of the weekend.
However, Sunday and Monday are more complicated. The
aforementioned high pressure system will move into the Atlantic
ocean and cause winds to veer across the Keys. More tropical
moisture will be directed towards the island chain in concert with
the veering winds to mark the start of the work week. Due to
increased CAPE and additional low level moisture, opted to put
a slight chance of thunderstorms back into the forecast for
Sunday and Monday. Details on where showers will form is not
certain at this time, and statistical guidance shows a range of 30
to 60 percent PoPs on Sunday night. Rainy season has not left yet,
though bouts of widespread shower coverage will become less
frequent towards the end of the month.

&&

.MARINE...
Issued at 423 AM EDT Fri Oct 17 2025
Small Craft Should Exercise Caution for all waters of the Florida
Keys today except for Florida Bay, where Small Craft Should
Exercise Caution for increasing winds. A Small Craft Advisory may
be required for all waters of the Florida Keys. From synopsis, a
high pressure system moving towards the southeastern CONUS form
the Great Lakes will support breezes freshening to moderate to
fresh today and tonight. Small Craft Advisories may be required as
breezes are expected to be just below the threshold. Shower
coverage will rise today as the wind surge moves south across the
Florida Keys coastal waters. Environmental conditions will become
more supportive of showers and thunderstorms on Sunday and Monday.

&&

.AVIATION...
(06Z TAFS)
Issued at 423 AM EDT Fri Oct 17 2025
VFR conditions are expected to prevail today. With that said,
there will be a chance for brief sub VFR conditions due to
expected passing scattered showers. Winds will be gentle to
moderate out of the northeast, freshening through the day.

&&

.CLIMATE...
In 1910, a category 3-4 Hurricane moved north northeast passing
about 25 miles west of Key West. A navy tug at the Dry Tortugas
reported a minimum pressure of 28.26" (957 mb) with calm lasting 40
minutes in the eye. At Sand Key the minimum pressure was 28.40" (962
mb) with wind estimated at 125 mph. In Key West, the minimum
pressure was 28.50" (965 mb) with wind gusts to 110 mb and a storm
tide of 15 feet and large swells to 15 feet along the western
shores. Tropical Storm winds lasted more than 30 hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  85  76  86  77 /  30  20  10  30
Marathon  84  76  84  77 /  30  10  10  20

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&

$$

Public/Marine/Fire...AJP
Aviation/Nowcasts....11
Data Acquisition.....11

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