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000
FXUS62 KKEY 210830
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
430 AM EDT Sun Apr 21 2024

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

.DISCUSSION...
Issued at 430 AM EDT Sun Apr 21 2024

Mostly clear, mild and dry conditions prevail along the Florida
Keys on this early Sunday morning, with radars detecting no
precipitation across the region. Temperatures are hovering in the
mid to upper 70s, with dewpoints in the upper 60s to near 70, and
winds on land from the southeast at 10 to 15 mph. Surface
analysis depicts weak high pressure over the western Atlantic,
with a frontal boundary draped from the Carolinas across South
Georgia and along the northern Gulf Coast. Aloft, a lower to mid
level ridge persists over the SE Gulf, and continues to control
the weather regime across South Florida and the Keys. Further
north, deep westerly flow prevails across the eastern CONUS, with
the upper level subtropical ridge suppressed far southward into
the Caribbean Sea. The 00Z Key West sounding reflected the
influence of the nearby ridge, with a couple of inversions below
850 mb, PW of 1.13 inches, and very dry lower to mid levels above
the inversion. More recent MIMIC-TPW satellite imagery shows
similar estimated PWs across our region, with higher PWs along the
frontal zone in the northern Gulf, and confined far to our south
over the Caribbean Sea.

Mostly sunny, dry and warm weather will prevail again today, as
the lower to mid level ridge continues to squash any shower
development. High temps will reach the mid 80s once again, with
dewpoints in the upper 60s to near 70 keeping RHs somewhat in
check.

A shortwave trough moving across the Southeastern states will
finally displace the lower-mid level ridge SW to near the Yucatan
tonight and Monday. This will allow the late season surface
front to slide through South Florida and the Keys Monday
afternoon/evening. While scattered showers and even some strong
storms are expected further north over the peninsula Monday
afternoon into the evening as this front moves through, it
appears that lack of available moisture and unfavorable difluent
low level flow should keep the Keys dry. We will keep an eye on
the far Upper Keys during the late afternoon and early evening
hours, when convection will probably be sliding offshore from
Miami-Dade County into the Atlantic waters. Following the frontal
passage, we expect legitimate northerly winds Monday night,
although temps and dewpoints will drop only a couple of degrees.

The forecast becomes more a bit murky heading into the middle of
the week, with a zonal flow pattern over the Gulf and Florida
suppressing the subtropical ridge to our south at all levels, and
sufficient lingering moisture to allow for at least isolated
showers. The latest guidance is less emphatic with a weak mid
level disturbance moving across the Gulf on Tuesday and through
the Keys Tuesday night. While a renegade MCS is always possible
with these synoptic patterns in late April, for now will continue
with just slight 10 to 20 percent shower chances from Tuesday
through Wednesday night. A drier airmass should spread back into
our area later in the week, as ridging aloft rebuilds over the
Gulf. Temps will remain near normal, with highs in the lower to
mid 80s and lows in the mid 70s. Dewpoints should hold in the mid
to upper 60s through the week, along with increasing easterly
breezes beginning around midweek, therefore outdoor conditions
will remain quite pleasant for late April.

&&

.MARINE...
Issued at 430 AM EDT Sun Apr 21 2024

Overnight observations show SE winds of 10 to 14 knots along the
reef and at Long Key C-MAN, with seas at Satan Shoal running
between 2.5 and 3 feet. No marine headlines are currently in
effect, and none are expected through Monday morning. There is
some potential for a period of Small Craft Exercise Caution late
Monday and Monday night as NW/N winds increase behind a front
moving through the Keys waters. From the synopsis, high pressure
over the western North Atlantic will retreat farther offshore
today, with southeasterly breezes slackening across the Florida
Keys coastal waters. Gentle southeast to south breezes tonight
into Monday will become moderate from the northwest to north
Monday afternoon and evening, as a weak frontal boundary slides
through South Florida and the Keys. High pressure over the
Southeastern states will bring moderate easterly breezes back to
the Keys waters by the middle of the week, with fresh breezes
developing later in the week.

&&

.AVIATION...
(06Z TAFS)
Issued at 430 AM EDT Sun Apr 21 2024

VFR and dry conditions will prevail at the EYW and MTH terminals
through the TAF period. Near surface winds will remain from the
southeast near 10 knots today, decreasing to around 5 knots this
evening.

&&

.CLIMATE...
On this day in 2012, the daily record rainfall of 1.99 inches was
recorded in Key West. Precipitation records for Key West date
back to 1871.

&&

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

$$

Public/Marine/Fire...Jacobson
Aviation/Nowcasts....AP

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