095
FXUS62 KKEY 110840
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
440 AM EDT Sat May 11 2024

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

.DISCUSSION...
Issued at 440 AM EDT Sat May 11 2024

Mostly clear, warm and dry conditions prevail along the Florida
Keys on this early Saturday morning, with radars detecting no
precipitation across the region. Temperatures range mostly from
the mid 70s to near 80 along the island chain, although the
typical cool spot at North Big Pine has radiated down to 70F under
clear skies and near calm winds. Surface analysis shows high
pressure over the distant central Atlantic, with a weak ridge
extending westward through the Straits of Florida, and a frontal
boundary draped across northern Florida and the NW Gulf of Mexico.
Aloft, broad troughing dominates most of the eastern CONUS, with
one shortwave exiting the Mid Atlantic region while another drops
through the western Great Lakes. The mid level ridge which has
dominated our weather regime for the past several days has been
pushed SW to the Bay of Campeche, although a low level ridge axis
persists across the southern Gulf and into the Straits. The 00Z
Key West sounding remained dry and stable, with low inversions
based near 1000 and 3500 feet, very dry air throughout the lower
to mid levels, and PW of only 1.20 inches (at the 25th percentile
for this date). Recent MIMIC-TPW satellite imagery shows a
similarly dry airmass persisting across the Keys and South
Florida, while a ribbon of higher moisture pushes southward into
central Florida ahead of the front.

Mostly clear, warm and dry weather will prevail across the Keys
through the weekend. Although the next shortwave moving across
the eastern CONUS will push the weak front down the Florida
peninsula today and tonight, this front will be starved for
moisture as it reaches our area, with dry air persisting in the
lower to mid levels as the ridge remains in place just to our
south. Have maintained a dry forecast through Sunday night, in
good agreement with MOS and NBM consensus. The front is expected
to stall over extreme South Florida on Sunday, then lift back
north as a warm front Monday. Here in the Keys, the only real
impact will be a period of gentle NW/N breezes tonight into
Sunday, and a brief interlude of lower dewpoints, possibly briefly
dropping into the 60s for some areas, on Sunday. Temps will
change little through the weekend, with highs in the upper 80s and
lows in the upper 70s to near 80.

Heading into next week, guidance has continued to trend slower and
more amplified with the next shortwave pushing east from the
Southern/Central Plains, maintaining a stronger lower to mid
level ridge over and just south of the Keys. Model time-height
cross sections show abundant dry air persisting through the lower
to mid levels. Confidence is increasing that convective activity
will remain to our north through at least Wednesday, and have
lowered PoPs to 10 percent or or less with no mention of thunder.
Thereafter, have continued with the existing forecast of 20 PoPs
and a mention of thunder, although the latest ECMWF suggests that
rain chances might be lowered further in later forecast cycles as
the ridge holds quite strong across our region. Otherwise, we
expect our first stretch of highs near 90F next week, with lows
only dropping to the lower 80s. Dewpoints will be heading upward
through the week as well, climbing into the mid/upper 70s by
midweek, with afternoon heat indices peaking at 100-105F. Summer
is almost here.

&&

.MARINE...
Issued at 440 AM EDT Sat May 11 2024

Late night observations show mostly S/SW around 5 knots along the
reef and at Long Key C-MAN, with seas at Satan Shoal running just
below 1 foot. No marine headlines are currently in effect across
the Keys coastal waters. From the synopsis, light to gentle
southwest to west breezes this morning will increase from the west
this afternoon off the Upper Keys, as a frontal boundary moves
down the Florida Peninsula. Winds will continue to veer around the
compass during the weekend as this front approaches and
dissipates in the vicinity of the Keys on Sunday. Gentle to
moderate southeast to south breezes will resume early next week as
another high pressure area moves over the western Atlantic.

&&

.AVIATION...
(06Z TAFS)
Issued at 440 AM EDT Sat May 11 2024

VFR conditions will prevail at the EYW and MTH terminals through
the TAF period. Light and variable near surface winds will become
southwest to west this morning, then will turn to west to
northwest in the evening hours at 5 to 10 knots.

&&

.CLIMATE...
On this day in 1983, the daily record cold high of 75F was recorded
in Marathon. This is also tied for the coolest high temperature ever
recorded in May for Marathon. Temperature records for Marathon date
back to 1950

&&

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

$$

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

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