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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KKEY 181848
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
248 PM EDT Sun Apr 18 2021

.DISCUSSION...
Satellite imagery indicates generally mostly sunny to partly
cloudy skies across the island chain. This has allowed
temperatures to easily climb into the mid to upper 80s.
Interestingly, despite increased lower-level moisture as well as
ample land heating, cloud streamers have had a tough time firing
north of the island chain today. This may be the result of the
winds collapsing a little quicker today compared to yesterday as
well as a slight backing of winds to southeast to south (instead
of yesterday`s southwesterlies). Expecting no rain for the
balance of this afternoon and evening for the island chain.

A frontal boundary is draped across Central Florida. This feature
will remain stalled for the next couple of days before slowly
creeping across Florida Tuesday and Wednesday. The general pattern
of mainly southerly winds peaking overnight into the morning
hours is expected to continue through Tuesday. With the
aforementioned increased moisture, there is a chance for a few
showers overnight tonight with the diurnal wind surge. A weak mid-
level pouch of vorticity will move east along the frontal
boundary Monday night, providing a large-scale source for ascent.
With another south to southwest wind surge, any convection that
fires over Cuba Monday afternoon may survive the trek to the
island chain. In addition, the available longer-range CAM model
guidance indicates some in- situ convective development south of
the island chain. Forecast soundings indicate moderate
instability, so have kept a mention of thunder during this period.

The front will finally push through the Florida Keys Wednesday
afternoon and evening. Although upper-level support will be
relatively benign, have kept PoPs at 30 percent for Wednesday and
Wednesday evening as the front pushes through (with the mention of
possible thunder). Thereafter, high pressure will build over the
Florida Peninsula for the rest of the work week. Temperatures will
tick down a few degrees, with the most noticeable difference
being a reduction in humidity. Dewpoints will likely bottom out in
the mid to upper 60s for Thursday and Friday. This may be one of
the last times we get to advertise that for some time.

&&

.MARINE...
A weak area of high pressure centered east of the Bahamas will
result in generally southerly flow through Tuesday. Breezes will
peak during the overnight and mornings, with noticeable lulls in
the afternoon and evenings. A frontal boundary will remain
stalled over the Florida Peninsula through Tuesday. The front will
finally slide southward through South Florida Tuesday night and
Wednesday, passing through the Keys coastal waters late Wednesday
afternoon and evening. In the wake of the front, gentle to
moderate northerly breezes on Thursday will veer toward the
northeast to east and freshen Thursday night through at least
Friday night.

&&

.AVIATION...
VFR conditions with brief bouts of MVFR ceilings are expected for the
island terminals through 18z/19th. Isolated showers activity may form
near both EYW and MTH late this evening and during the overnight,
however confidence in timing and coverage is low. Will leave it out
at this time, but short-term amendments and TEMPOs may be needed.

&&

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

$$

Public/Marine/Fire...BT
Aviation/Nowcasts....Williams
Data Acquisition.....DR

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