Duck Key, Florida Weather Forecast Discussion

328
FXUS62 KKEY 300807
AFDKEY
Area Forecast Discussion
National Weather Service Key West FL
407 AM EDT Tue Sep 30 2025
...New DISCUSSION, MARINE, AVIATION...
.DISCUSSION...
Issued at 407 AM EDT Tue Sep 30 2025
The radar has quieted down during the overnight. We had some
residual showers moving off the mainland earlier in the period
that have since moved out of our area. More recently some showers
have developed along narrow corridors of convergence across the
Straits of Florida. Otherwise, Tropical Storm (TS) Imelda
continues to slowly move northward along the Florida East Coast.
This is promoting a northwest wind for the Florida Keys, that has
been breezy at times, especially in the Middle and Upper Keys.
.FORECAST...
As Imelda continues to move north and then makes it sharp turn to
the east, high pressure will gradually fill in behind. This will
allow the pressure gradient to eventually lessen and winds will
slacken. At the same time, winds will periodically fluctuate
between northwest to northeast as the building ridge battles with
daytime heating across the Florida Peninsula at times. Moisture
wrapping around the broad cyclonic envelop associated with Imelda
will occasionally pivot across the region. That being said, rain
chances will still be near normal. The only exception may be the
Upper Keys where convection will tend to drift off the mainland,
given a northerly steering flow.
As we go through the first several days of October, the high will
build as it pushes east and press against the Keys. This will
allow for easterly winds to return, however, the exact strength
will depend on how far south the high builds. The ECMWF at this
point as a weaker high and thus lighter winds with a southeast
tendency. The GFS is much stronger with the potential of moderate
to fresh breezes returning. Another feature we will have to
eventually keep an eye on will be a quasi-stationary frontal
boundary that will develop as the high builds. This feature should
stay well to our north but it could have impacts to our rain
chances later in the period.
&&
.MARINE...
Issued at 407 AM EDT Tue Sep 30 2025
Small Craft Advisories remain active for the easternmost Straits
of Florida. Across the Hawk Channel, Florida Bay, and remaining
Straits of Florida, Small Craft Exercise Caution headlines are in
effect. From synopsis: Tropical Storm Imelda, located east of the
northeast coast of Florida, will continue to move slowly
northward, then make a sharp eastward turn today into the west-
central North Atlantic. Moderate to fresh northwesterly breezes
will slacken by tonight. High pressure over the Eastern Seaboard
will slowly slide eastward into the western North Atlantic, with
mainly gentle northwesterly breezes eventually veering to the
northeast to east for the middle to latter part of the work week.
Winds will then clock around towards the southeast towards the end
of the week and into the upcoming weekend.
&&
.AVIATION...
(06Z TAFS)
Issued at 407 AM EDT Tue Sep 30 2025
VFR conditions prevail at both EYW and MTH for the 06Z TAF period.
Shower coverage will be minimal, though a stray shower is possible
during the day. Brief periods of MVFR CIGs are possible, but
coverage is not extensive enough to warrant mention. Winds will
remain northwesterly and gusty through the afternoon. Gusts are
forecast to weaken after sunset.
&&
.CLIMATE...
On this day in Keys Weather History, in 1945, a record low
temperature of 69 was recorded at Key West. This is also tied for
the coldest temperature recorded during the month of September.
Temperature records for Key West dates back to 1872.
&&
.PRELIMINARY POINT TEMPS/POPS...
Key West  89  79  88  79 /  10  20  20  30
Marathon  89  79  88  79 /  20  30  30  30
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ052-072.
&&
$$
Public/Marine/Fire...LIW
Aviation/Nowcasts....LIW
Data Acquisition.....AJP
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NWS KEY Office Area Forecast Discussion