Duck Key, Florida Weather Forecast Discussion

908
FXUS62 KKEY 090830
AFDKEY
Area Forecast Discussion
National Weather Service Key West FL
430 AM EDT Tue Sep 9 2025
...New DISCUSSION, MARINE, AVIATION...
.DISCUSSION...
Issued at 231 AM EDT Tue Sep 9 2025
Broad mid to upper level troughing blanketing eastern North
America reaches southward into the Gulf this morning. With that
said, a shortwave trough is lifting out across New England and is
yanking out the eastern half of a persistent surface trough
straddling the Florida Peninsula. At least for today, the western
half of this trough will remain balled up in the eastern Gulf and
contribute to a moist and confluent zone across Florida and the
Keys. Support aloft is expected to be neutral. With that said,
some guidance suggests the steering flow will veer further
southwest. This against the back drop of a moist and confluent
boundary layer will result in a heightened potential for showers
and thunderstorms. Will advertise likely PoPs for today.
The Atlantic ridge will make a brave attempt to swing
northwestward into the Keys tonight as surface trough to our north
lifts a bit to the north and weakens. Guidance suggests some
drying and stabilization will occur and help bat rain chances down
to near normal. With that said, shut down is not expected as
moisture and instability is expected to remain ample and the weak
flow will allow for the usual mesoscale and diurnal triggers. The
lower level ridge will remain across our area after mid week.
Moisture will remain high, as will CAPE, keeping rain chances near
to slightly above normal.
Uncertainty ramps up considerably later in the week and weekend.
Guidance suggests a stagnant front that has been draped across
north and central Florida for an eternity will begin advancing
southward into South Florida on Friday and possibly into the Keys
this weekend. This will be driven by a complicated
reamplification of the mid latitude trough still sitting over the
eastern United States. One model solution suggests a prefrontal
trough will push through the Keys this weekend. Any sort of mid
latitude push this time of year usually results in a very wet
stretch. For now will maintain current forecast trends with PoPs
climbing to likely by Friday and persisting into the weekend.
&&
.MARINE...
Issued at 231 AM EDT Tue Sep 9 2025
A double barreled low straddling the Florida Peninsula this
morning is expected to pull northward and further away from the
Keys over the next day or two. At least for today, Keys waters
will remain in a fairly moist and confluent zone around the Gulf
low`s southeastern periphery. Consequently, expect periods of
above normal convective coverage today, paring back to near or
slightly above normal today. Winds will generally remain light out
of the south to southwest but with periods of variability. A
sloppy pressure field will prevail through mid week, resulting in
light and often variable breezes. A front is expected to sag
southward down the Florida Peninsula later in the week, resulting
in more consistent light to gentle northeasterly breezes.
&&
.AVIATION...
(06Z TAFS)
Issued at 231 AM EDT Tue Sep 9 2025
VFR conditions are expected to largely prevail this morning at EYW
and MTH, though a chance of occasional passing showers and
thunderstorms will provide an opportunity for periods of sub-VFR
conditions. Thus, VCSH is included through 18z for now, but timing
and placement of shower activity is uncertain due to their being
driven by boundaries and other localized triggers. For this reason,
mention of more specific impacts and categorical changes will be
handled by future updates and amendments. Winds will generally be
from the south to southwest at 5 to 10 knots.
&&
.CLIMATE...
On this day in 1919, a category 4 Hurricane moved west-northwest
through the Straits. It passed just south of the Key West, which
recorded a minimum pressure of 28.81" (976 mb), a daily-record 5.61"
of rain (along with another daily-record 7.47" of rain on the 10th),
and the anemometer cups blew away at 80 mph. Tropical Storm force
winds lasted more than 38 hours. At Sand Key a minimum pressure of
28.35" (960 mb) was recorded, and the anemometer cups blew away at
84 mph wind, after which a peak wind of 110 mph was estimated. At
the Dry Tortugas the minimum pressure was 27.51" (932 mb), and a
ship near the Dry Tortugas recorded a minimum pressure of 27.36"
(927 mb). Many homes were unroofed, 10 ships were lost, and about
500 people were killed.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...11
Aviation/Nowcasts....MC
Data Acquisition.....MC
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NWS KEY Office Area Forecast Discussion