Key Colony Beach, Florida Weather Forecast Discussion

916
FXUS62 KKEY 241850
AFDKEY
Area Forecast Discussion
National Weather Service Key West FL
250 PM EDT Wed Sep 24 2025
...New AVIATION, PREV MARINE, DISCUSSION, AND FORECAST...
.AVIATION...
(18Z TAFS)
Issued at 230 PM EDT Wed Sep 24 2025
VFR conditions are expected to prevail at the terminals through
the TAF period. Earlier shower activity has diminished, but a
chance (30%) for showers and thunderstorms remains for this
evening. While any shower or thunderstorm is likely to produce
brief MVFR CIGs and MVFR to IFR visibility, explicit mention of
these in the TAFs will be left to future amendments as necessary
due to the anticipated uncertainty and limited areal coverage.
Winds should remain light to gentle from the northeast this
afternoon, becoming light and possibly variable overnight.
&&
.MARINE...
Issued at 943 AM EDT Wed Sep 24 2025
Scattered showers and thunderstorms will persist across Keys
coastal waters this afternoon. High pressure centered over the
western North Atlantic will dominate the pattern through Saturday.
This will promote light to gentle northeast to east breezes
through early Thursday. The aforementioned high will begin to
loosen its grip across the region as an area of low pressure tries
to develop in the vicinity of the Bahamas. Expect mostly north to
northeast breezes, occasionally variable through Saturday as a
result. Light to gentle northwest to north breezes are anticipated
to flourish as the system moves northwestward.
&&
.PREV DISCUSSION...
Issued at 943 AM EDT Wed Sep 24 2025
A quiet and dry early morning has given way to recent development
of scattered showers and isolated thunderstorms to the south of
the Island Chain. These showers are developing along leftover
boundaries from yesterday`s convective activity. This morning`s
12z KKEY sounding depicts typical moderate instability in the form
of MLCAPE over 2300 J/kg, but this is counterbalanced by a
relatively dry layer from just above the surface to about 500mb. A
shallow inversion was present as the base of this layer, but
daytime heating is likely to overcome this. Thus, scattered
showers are likely to continue through this afternoon, though they
should be largely weak and short-lived owing to the dry layer.
G19 visible satellite depicts few to scattered low- level cloud
cover, enabling temperatures to already be rising into the upper
80s, to reach around 90F this afternoon. Surface dew points remain
in the upper 70s to near 80F. With the existing forecast holding
30 percent PoPs, no changes are anticipated for this afternoon.
&&
.FORECAST...
Issued at 430 AM EDT Wed Sep 24 2025
The next several days can be summed up quite easily. High pressure
will remain the dominant feature across the Atlantic with the
southwestern periphery of this ridge extending into Florida.
Residual moisture will remain in the low levels fluctuating from
time to time. Moisture remains quite high yet again with GOES East
Total Precipitable Water (TPW) showing PWAT values of 1.8 to 2
inches across the Keys. Any shower and thunderstorm activity today
most likely will be driven by mesoscale processes, leftover
boundaries, as well as any speed or directional convergence. Rain
chance today and tonight remain at 30% as a result. Slightly drier
air begins to encroach on the Keys Thursday continuing into at
least the first half of the weekend. Rain chance is at 20% which
is slightly below normal for this time of the year. There is the
possibility during this time frame for some cloud lines once winds
become light and variable, especially Friday. Otherwise, expect
more in the way of summertime heat with highs near 90 and
overnight lows in the lower 80s. There won`t be much relief
overnight outside of any shower or thunderstorm.
Then the forecast gets quite interesting. However, model guidance
overnight seems to be coming into agreement on a solution. The
National Hurricane Center is monitoring two areas for potential
tropical development over the next couple to few days. The one
farthest to the east (AL93) has an 80% chance of development
within 48 hours and 90% chance of development within 7 days. The
one a little further west currently over the Lesser Antilles
(AL94) has a 30% chance of development within 48 hours and 80%
chance of development within 7 days. As of now, it appears both of
these systems, whatever they become, may turn northwestward
moving either over or parallel to the Bahamas. However, this
opportunity would serve as a good reminder to make sure you are
prepared should the forecast lead to more of a threat to the
Florida Keys. These two areas being monitored currently do not
pose a threat to the Keys, but they will continue to be watched.
For the latest, visit www.hurricanes.gov and www.weather.gov.
Since the latest guidance keeps everything mostly east of the
Keys, the forecast for now continues with slight chances of rain
at 20%. A 30% chance of rain is in place for Saturday night and
Sunday due to a slight moisture increase. If everything stays
east of the Keys, drier air is expected to be dragged southward
keeping rain chances at 20% thereafter. This would also lead to a
northwest to northerly wind flow.
The upper level pattern here suggests a fairly deep trough to be
over Florida (currently moving into the Southeast United States)
and in the vicinity which would act to cause any system to curve.
However, details remain murky at best. Stay tuned for the latest
information as the forecast could change frequently over the next
few days.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...MC/MJV
Aviation/Nowcasts....MC
Data Acquisition.....MC
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NWS KEY Office Area Forecast Discussion