838
FXUS62 KKEY 070830
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
430 AM EDT Fri Jun 7 2024

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

.DISCUSSION...
Issued at 430 AM EDT Fri Jun 7 2024

Convective evolution during the past several hours is a good
example of the difficulty in forecasting wet season rain chances
here in the Florida Keys, even in the near term. In spite of a
favorable synoptic environment, a moist and unstable airmass as
sampled by the 00Z Key West sounding, and ample available
boundaries to act as triggers, convection was confined primarily
to the offshore Gulf waters, with only a few spots between
Marathon and Big Pine seeing any measurable rainfall during the
night. More recently, all activity has dissipated, with radars
currently detecting no precipitation across the area. Temperatures
along the island chain are hovering in the lower to mid 80s, with
sticky dewpoints in the mid to upper 70s, and winds on land mostly
from the southwest at 5 to 10 mph. Surface analysis depicts weak
high pressure over the central Atlantic, with a front extending
from the Mid Atlantic to the Southern Plains, and a weak trough
over Florida. Aloft, water vapor imagery shows a trough moving
across the NE Gulf of Mexico. As noted above, our local sounding
was quite moist and unstable, with SBCAPE over 4000 J/KG and PW of
2.03 inches (above the 90th percentile for the date). Recent
MIMIC-TPW satellite imagery shows a similarly moist airmass
remaining in place across the Keys area.

Despite the current lack of activity across the area, the nearby
trough aloft plus ample available moisture and instability
indicate that convection should redevelop across the region
sometime during the day. This is depicted by most of the CAM
guidance, albeit with variations on where exactly the activity
will focus. Have nudged PoPs up a notch to 50 percent for today,
and 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.

Rain chances should remain above climo tonight and Saturday, as
the trough aloft slowly trudges SE across the Florida peninsula,
with ample moisture remaining in place. We then expect a
relatively drier period for Saturday night through Sunday night as
mid level ridging temporarily noses into the area, although light
low level flow and lingering moisture will allow ample opportunity
for mesoscale interactions to spark convection. Have generally
kept PoPs near the MOS consensus, but well below the very high NBM
numbers through the weekend.

Heading into next week, guidance is in general agreement with a
trough aloft developing once again over the Gulf, but differences
persist with the strength and location of this feature, as well as
with any surface low or trough development. While it appears
increasingly likely that a plume of deep tropical moisture will
extend northward from the western Caribbean into the Gulf and
across parts of Florida during the middle to later part of next
week, it remains unclear if the Keys will be within or just to the
east of this plume. For now, have nudged PoPs up to 50 percent,
which is well above June climo, from Tuesday through Thursday.
Further adjustments will be likely needed during the next few
days.

&&

.MARINE...
Issued at 430 AM EDT Fri Jun 7 2024

Overnight observations show S/SW winds of 5 to 10 knots along the
reef and at Long Key C-MAN, with seas at Satan Shoal running
around 1.5 feet. No marine headlines are currently in effect, and
none are expected through the weekend. From the synopsis, weak
high pressure over the central North Atlantic will slide further
eastward through the weekend, as a frontal boundary stalls 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 become
gentle to moderate early next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 430 AM EDT Fri Jun 7 2024

VFR conditions will prevail at EYW and MTH through the 08/06Z TAF
period. Near surface winds will be southerly outside of showers
between 5 and 10 knots. Showers in the waters around EYW and MTH are
expected today, but hi-res guidance does not agree on where and when
showers will develop, therefore TEMPO groups are left out of the
TAFs.

&&

.CLIMATE...
On this day in Keys Weather history, in 2008 at The Florida Keys
International Airport at Marathon, a record daily low temperature of
65F was recorded. This observation tied for the coldest temperature
ever recorded in the month of June. Temperature records at Marathon
date back to 1950.

&&

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

$$

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

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