941
FXUS62 KKEY 080830
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
430 AM EDT Sat Jun 8 2024

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

.DISCUSSION...
Issued at 430 AM EDT Sat Jun 8 2024

After a very active late afternoon and early evening across parts
of the Keys island chain and surrounding waters, convection has
remained in check during the late night hours, as the atmosphere
recovers from the earlier activity. Currently, radars detect
scattered showers over the eastern Straits of Florida, with a more
substantial cluster of showers and storms further to the east
over the Atlantic waters. Skies are mostly clear to partly cloudy
along the island chain, with temperatures in the lower 80s,
dewpoints in the mid to upper 70s, and winds on land from the
south to southwest around 10 mph. Surface analysis depicts weak
high pressure over the central Atlantic, with a frontal boundary
draped from off the Mid Atlantic coast across the Southeastern
states and into the Lower Mississippi Valley. Aloft, water vapor
imagery shows a trough axis extending from off the Southeastern
U.S. coast to the SE Gulf of Mexico. The 00Z Key West sounding
sampled a moist and conditionally unstable airmass, with no
significant inversions present, and PW of 2.14 inches (above the
90th percentile for the date). Recent MIMIC-TPW and GOES-TPW
satellite imagery shows a similarly moist airmass remaining in
place across the Keys area.

With plenty of moisture in place and a nearby trough aloft, it is
likely that convection will fire up once again across the area
later on today. There may be some potential for a reverse cloud
line as well, although low level SSW flow would probably push any
cloud line north of at least the Lower Keys. While the CAM
guidance suite varies as usual with the placement and timing, have
sufficient confidence to continue with above climo 50 percent
PoPs for today. Have also continued with chance thunder wording,
as any convection that develops certainly will have the potential
to produce lightning. Otherwise, expect another typically hot and
humid day for early June, with high temps near 90, dewpoints in
the upper 70s, and max heat indices of 100-107F.

We expect a somewhat drier period for tonight through Sunday
night as the trough axis moves to our east and mid level ridging
temporarily noses into the area, although light low level flow and
ample moisture will allow continued opportunity for mesoscale
interactions to spark convection. Have generally kept PoPs in the
30-40 percent range, which is near the MOS consensus, but well
below the very high NBM numbers.

Confidence is gradually increasing that we will see a prolonged
period of wet weather next week, as guidance has come into
somewhat better agreement with development of broad troughing
aloft over the Gulf. While the latest GFS is much more emphatic
with surface low development as compared to the ECMWF, even the EC
depicts a favorable pattern for rainfall through much of the
week, with deep and very moist southerly flow across the Keys on
the east side of the Gulf trough. Accordingly, have nudged PoPs up
to 60 percent for Tuesday night through Thursday. The end of the
work week may be just as wet, but am not confident enough yet to
bump up to likely PoPs that far out in time. High temps should be
suppressed slightly into the upper 80s due to cloud cover and
frequent rainfall.

&&

.MARINE...
Issued at 430 AM EDT Sat Jun 8 2024

Late night observations show S/SW winds ticking up slightly to
near 10 knots along the reef and at Long Key C-MAN, with seas at
Satan Shoal running around 2 feet. No marine headlines are
currently in effect, and none are expected through the weekend.
From the synopsis, weak high pressure will remain over the
central North Atlantic, as a series of frontal boundaries stall
off the Eastern Seaboard and over north Florida. This will result
in light to gentle southerly breezes across the Keys coastal
waters through Monday. Southeast to south breezes will likely
increase to gentle to moderate from Monday night through midweek.

&&

.AVIATION...
(06Z TAFS)
Issued at 430 AM EDT Sat Jun 8 2024

VFR conditions will prevail at EYW and MTH early in the TAF period.
After sunrise, a surge in environmental moisture and slightly
shifting winds will allow an increase in shower and thunderstorm
coverage near the island terminals. Despite high confidence in the
environment becoming more favorable, timing when and where showers
may form is difficult as hi-res models do not show consensus. Thus,
the terminals have a broad mention of VCSH. Near-surface winds
outside of showers will be generally southerly at 6 to 10 knots.

&&

.CLIMATE...
On this day in Keys weather history in 1966, Hurricane Alma moved
north off of Cuba and intensified to a Category 3 hurricane and
passed about 35 miles west of Key West. The Dry Tortugas measured
sustained winds of 125 mph while Key West measured winds of 60 mph
with gusts to 70 mph. Hurricane Alma was the only hurricane to
affect the Keys during the month of June in the last hundred
years.

&&

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

$$

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

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