134
FXUS62 KKEY 290927
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
427 AM EST Sat Nov 29 2025

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

.KEY MESSAGES...

-Increasing moisture, instability, and freshening breezes this
 afternoon and evening will lead to chances of rain along with the
 potential for thunderstorms.

-Breezy to windy conditions continue through early this evening,
 before slackening later in the evening and overnight.

-Small Craft Advisories conditions are expected for all Keys
 coastal waters through tonight.

&&

.DISCUSSION...
Issued at 427 AM EST Sat Nov 29 2025
The cool snap continues across the Florida Keys early this
morning. Temperatures along the Island Chain have been quite
steady overnight remaining in the mid 60s with dew points in the
lower 60s. The cool temperatures are being met with a consistent
breeze giving it the Florida winter chill to the air. Strong
surface high pressure is centered over the Appalachian Mountains
of Virginia and West Virginia. This continues to promote moderate
to fresh northeast to east breezes at marine platforms surrounding
the Island Chain. Gentle to moderate breezes prevail at
communities along the Island Chain. GOES East Nighttime
Microphysics imagery shows most of the cloud cover remaining
over the marine waters to the south and west of the Island Chain
with KBYX radar not detecting any showers associated with these
clouds.

.FORECAST...
The forecast for the next several days will be dominated by a
series of high pressure systems traversing across the eastern
United States. This will keep a healthy pressure gradient across
the area resulting in moderate to fresh northeast breezes this
morning strengthening to fresh to strong northeast to east
breezes for this afternoon and evening. The cold front that moved
through yesterday will start to move back to the northwest as a
warm front shifting breezes to the northeast to east. Also,
looking at GOES Total Precipitable Water (TPW) products, the
leading edge to much moister air is loitering just outside of the
Keys coverage area where PWAT values of 1.4 to 1.7 inches are
being estimated compared to 0.7 to 1 inch currently over the Keys.
Since we have a moisture, wind, and instability surge waiting in
the wings, there will no doubt be an expected increase in shower
activity across the area later this afternoon and evening.
Therefore, timing was introduced to the forecast keeping slight
chances in this morning for the Island Chain with chances for the
afternoon and tonight. All the ingredients are coming together for
an active afternoon and evening. Most of this shower activity
will be driven by speed convergence across the area with some
directional convergence. Add in the instability to this and now
these collisions can lead to potential for thunderstorms in a
ripened moist environment, especially over the Straits.

Breezes will begin to dramatically slacken overnight Saturday into
Sunday. Another high will move across the eastern United States
taking the place of the previous high, though, this one won`t be
as strong. Therefore, expect mainly gentle to moderate northeast
to east breezes to continue through Monday evening before
shifting to the east to southeast and further slackening overnight
through Tuesday night. Moisture will remain with the main
catalyst for showers being driven by mostly speed or directional
convergence and other mesoscale processes or remnant boundaries.

Another frontal boundary is expected to approach the Keys mid to
late week due to a developing coastal low off the Carolina coast.
However, before the front approaches, there may be a time frame
where the winds go light and variable along with dew points
climbing into the lower to mid 70s due to the southeast to south
breezes pumping up the dew points. Observations in Florida Bay
would suggest SST`s in the mid to upper 60s. If the dew points
are able to get close to this along with light and variable wind
flow, there may be a window of time for sea fog to develop. We
continue to keep an eye on this. The details still remain murky in
regards to the front. Some guidance pushes this front through and
others stall it right over the Keys. Details will become clearer
in the coming days. Stay tuned!

&&

.MARINE...
Issued at 427 AM EST Sat Nov 29 2025
A Small Craft Advisory remains in effect across all the Florida
Keys coastal waters for today. From synopsis, a frontal boundary
south of the area, paired with a dominant surface high over the
eastern CONUS, will maintain fresh to strong northeasterly breezes
today, and Small Craft Advisories will likely extend through
tonight. As the front decays and the high shifts northeastward,
breezes will begin to slacken by early Sunday. Another cold front
may be on the horizon for the middle of the week, reflected in the
breezes turning around the clock ahead of it. Shower activity
will wax and wane throughout the marine forecast period.

&&

.AVIATION...
(06Z TAFS)
Issued at 427 AM EST Sat Nov 29 2025
VFR and east northeast wind gusts near 25 knots will prevail
through much of the TAF period. A warm front will lift northward
through the terminals this evening, and TEMPO periods of MVFR
CIGS/IFR VIS within SHRA, and potentially TSRA, are possible.
Confidence in timing remains low, so have included VCSH at this
time.

&&

.CLIMATE...
On this day in 1896, the temperature fell to 51 degrees below
zero in Havre, Montana. Temperature records in Key West date back
nearly 150 years, and the coldest temperature ever recorded is 41
degrees, brrr!

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  77  72  79  74 /  40  50  20  10
Marathon  77  73  80  73 /  40  50  20  20

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory until 5 PM EST this afternoon for
     GMZ031>035-042>044-052>055-072>075.

&&

$$

Public/Marine/Fire...MJV
Aviation/Nowcasts....CLR
Data Acquisition.....CLR

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