373
FXUS62 KKEY 060830
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
430 AM EDT Thu Jun 6 2024

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

.DISCUSSION...
Issued at 430 AM EDT Thu Jun 6 2024

Mostly clear, warm and humid conditions prevail along the Florida
Keys on this early Thursday morning, with radar detecting only
isolated showers in the distant Straits and the offshore Gulf
waters. Temperatures are hovering in the lower to mid 80s, with
dewpoints in the mid to upper 70s, and winds on land from the
southeast around 5 mph. Surface analysis depicts weak high
pressure over the western Atlantic, with a cold front extending
from the Great Lakes southward into central Texas. Aloft, water
vapor imagery shows a mid level trough moving across the Lower
Mississippi Valley and the northern Gulf, with zonal flow
downstream over Florida, and the subtropical ridge suppressed
southward into the Caribbean Sea. The 00Z Key West sounding
sampled a conditionally unstable airmass up to a weak inversion
based near 600 mb, with near normal PW of 1.76 inches, although a
fair amount of dry air was present in the lower and especially in
the mid levels above the inversion.

Today should remain mostly dry with ample sunshine, similar to the
past few days, as the lack of any strong forcing combined with a
rather unfavorable mesoscale regime (weak and generally difluent
SE flow) and dry mid levels result in just isolated showers and
storms at most. Have retained the existing 20 percent PoPs.
Otherwise, high temps near 90 combined with dewpoints in the mid
to upper 70s will result in max heat indices of 100-105F during
the afternoon.

The mid level trough initially over the northern Gulf will
continue to drop slowly SE across Florida through the end of the
work week and into the weekend. Meanwhile, surface high pressure
will slide further offshore, as a cold front sags southward into
north Florida. This will result in a somewhat more favorable
large-scale environment for rainfall across our region, although
the mesoscale regime will remain questionable with mostly weak
S/SW flow prevailing. Have nudged PoPs up slightly for most
periods from tonight through Sunday, but held mostly to low to
mid chance, well below the very high NBM PoPs and close to the
MOS consensus. There should be a period of lower rain chances
centered on Saturday night, when a mid level ridge over the Gulf
nudges eastward into our area.

Forecast confidence remains quite low beginning early next week.
The latest guidance generally agrees on a deepening mid latitude
trough across the eastern CONUS, but continues to present a
variety of solutions regarding evolution of the Central American
Gyre and possible surface low development somewhere near the
Yucatan Peninsula. Regardless of the details, deterministic and
ensemble guidance suggest the potential for deep moisture to surge
northward into our area, with the latest EC ensemble mean PW near
or above 2 inches from Monday onward. As noted previously, there
may be a strong moisture gradient somewhere in our region, based
on where the gyre ultimately sets up. For now, have continued with
above normal rain chances, expecting adjustments to the forecast
during the next few days as the expected weather pattern becomes
more clearly defined.

&&

.MARINE...
Issued at 430 AM EDT Thu Jun 6 2024

Late night observations show E to SE breezes easing to 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 western Atlantic will slide
further offshore through the end of the week as a frontal
boundary stalls off the Eastern Seaboard and over north Florida.
This will result in gentle southeast breezes across the Keys
coastal waters today, becoming light to gentle from the south to
southwest from Friday through the weekend and into early next
week.

&&

.AVIATION...
(06Z TAFS)
Issued at 430 AM EDT Thu Jun 6 2024

VFR conditions will persist at EYW and MTH through the upcoming TAF
period. Near surface winds will be east to southeast at 5 to 10
knots. Occasional showers cannot be ruled out near the island
terminals, but the confidence is too low to include a VCSH group in
the TAF.

&&

.CLIMATE...
On this day in Keys Weather history, in 1881 at Key West a daily
record high temperature of 96F was recorded. This observations also
marks the warmest temperature ever recorded in June at Key West.
Temperature records at Key West date back to 1873.

&&

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

$$

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

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