794
FXUS62 KKEY 180845
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
445 AM EDT Sat May 18 2024

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

.DISCUSSION...
Issued at 445 AM EDT Sat May 18 2024
It`s yet another unseasonably warm morning in the Florida Keys.
Current temperatures across the island chain are in the lower to
mid 80s and dewpoints close behind with values near 80. KBYX is
once again clear of any precipitable echoes as mean layer ridging
is suppressing convective development across South Florida and
the Western Caribbean. Cloud cover is generally confined to
isolated patches of shallow cumulus in the Straits of Florida.

As our synoptic pattern remains relatively unchanged from
yesterday, we are expecting another hot day today. Usually, this
would be a good time to look for developing thunderstorms but
weakening southerly breezes due to mainland heating and a fairly
dry mid to upper level atmosphere will choke out any possible
showers. Unfortunately, this has little effect on our low level
moisture meaning that dewpoints will continue to be in the upper
70s today. As a result, a Heat Advisory will be in effect from 10
AM this morning until later this evening as heat index values are
forecast to reach up to 110 degrees. Tonight will also be a repeat
of previous nights with breezes freshening with the cooling of
South Florida`s temperatures and low temperatures in the lower to
mid 80s.

Sunday will also be another hot day across the Keys, only this
time some of our synoptic puzzle pieces will start to shift.
Sunday night into Monday, the deep layer ridging will shift east
towards the Atlantic as a mid latitude trough settles on the
ridge`s northeast periphery and slides into the Gulf of Mexico
from the Midwest. Guidance continues to be consistently
conflicted on how much low level moisture will be available with
this trough`s approach. Opted to hold chance PoPs and slight
chance thunder from Sunday night into Tuesday. Temperatures should
start to return near normal at the start of the week as well with
breezes shifting to the north. There`s still a chance that this
will advect some lower dewpoints into our area in the middle of
the week, but the signal is certainly not as strong as it was a
few days ago. Stay tuned.

&&

.MARINE...
Issued at 445 AM EDT Sat May 18 2024
Currently no watches, warnings, or advisories are in effect for
the Florida Keys coastal waters. From synopsis, the western
extent of a low-level ridge axis extends west-northwest through
the Bahamas and across the Keys. Southeast breezes will tend to
peak and lull overnight through Sunday as the heating and cooling
of South Florida and Cuba modulate the local wind forecast. There
may be a break in the rain-free conditions Sunday night through
Tuesday, followed by variable breezes Tuesday through Wednesday.

&&

.AVIATION...
(06Z TAFS)
Issued at 445 AM EDT Sat May 18 2024
VFR conditions are expected through tomorrow morning at EYW and MTH.
Surface winds will oscillate between south southeast and east
southeast over the course of the TAF period, remaining between 6 to
12 knots.

&&

.CLIMATE...
On this day in 1994, the daily record rainfall of 2.52" was recorded
in Marathon. Rainfall records date back to 1950.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  92  82  92  79 /   0  10  20  30
Marathon  91  83  91  80 /  10  10  20  30

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 10 AM this morning to 6 PM EDT this evening
     for FLZ076>078.

GM...None.
&&

$$

Public/Marine/Fire...JAM
Aviation/Nowcasts....NB
Data Acquisition.....NB

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