007
FXUS62 KKEY 140848
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
448 AM EDT Wed Aug 14 2024

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

.DISCUSSION...
Issued at 448 AM EDT Wed Aug 14 2024

Despite the early hour, heat indices remain around 100 degrees
across the island chain. Temperatures have struggled to drop any
further than the mid 80s and dew points have held steady in the
upper 70s to near 80 degrees. A few island communities have
experienced a brief cooldown with some of the shower activity
passing through, but the bulk of the convection has remained
south of the island chain. CIMSS MIMIC TPW places the Keys in a
swath of robust moisture, with drier air on its heels near Andros
Island. A ridge axis remains across South Florida and is maintaining
gentle breezes this morning.

With the aforementioned drier air encroaching on our eastern
waters this morning, we may see a decrease in shower activity
later this evening. The drier air does not appear to be moving
fast enough at this time to hamper shower activity through at
least late morning into early afternoon, so have bumped PoPs to
30% for today.

Tropical Storm Ernesto is just north of Puerto Rico and is moving
to the northwest. An upper-level trough across the Eastern
Seaboard will start to drive Ernesto to the north to northeast as
it becomes the main steering mechanism over the next day or so. In
terms of the weather back home, the same upper trough will cause
the Atlantic rigde to recede to the east. This will allow our wind
field to collapse by this afternoon, when winds are forecast to
become light and variable. With light winds, mesoscale processes
such as boundary collisions, cloud lines, and mainland convection
drifting south will be the main drivers of convection through most
of the extended forecast.

Looking ahead to the end of the week, a backdoor boundary will sag
southward down the Florida peninsula before washing out across
Central/South Florida. Deep tropical moisture ahead of it will
bring increased rain chances Friday through Saturday. This washed
out boundary will slide across the Keys on Saturday night, which
will bring dew points down a degree or two and hopefully put us
just out of Heat Advisory criteria. Ahead of this boundary,
oppressive dew points will remain in place, and temperatures will
peak in the lower to mid 90s each day. Some communities
experienced heat index values in the 113-115 degree range
yesterday, and with similar conditions in place today, an
Excessive Heat Warning is not out of the question. Have held off
for now and stuck with a Heat Advisory for today. We will continue
to monitor near term temperature and dew point trends closely.

&&

.MARINE...
Issued at 448 AM EDT Wed Aug 14 2024

There are no watches, warnings, or advisories in effect for the
Florida Keys coastal waters. An Atlantic ridge axis stretching
west across South Florida will support light to gentle easterly
breezes through this afternoon before becoming variable. Breezes
will shift to the northwest by Thursday night as a trough dips
south along the Eastern Seaboard. As the ridge axis fractures over
the Florida Peninsula, breezes will become more chaotic for
Friday through Sunday. Strengthening Tropical Storm Ernesto near
the Leeward Islands will slowly turn northward, likely impacting
the island of Bermuda as a hurricane Friday night through
Saturday.

&&

.AVIATION...
(06Z TAFS)
Issued at 448 AM EDT Wed Aug 14 2024

VFR conditions are expected to prevail at both EYW and MTH today. A
broken line of nocturnal showers will cross the island chain this
morning resulting in a VCSH mention in the TAFs. Afterwards, while a
shower cannot be ruled out, exact location and timing is too
uncertain to include mention. Near surface winds will be generally
out of the east at 4 to 9 knots early, becoming light and
variable.

&&

.CLIMATE...
On this day in 2021, the remnants of Tropical Storm Fred moved southwest
of Key West on August 14th. Fred produced maximum sustained winds
of 32 mph (maximum wind gusts of 45 mph), while Smith Shoal
Light, Sand Key Light, and Sombrero Key measured maximum sustained
winds of 34 knots (maximum wind gusts of 50 knots, 40 knots, and
40 knots, respectively). Maximum rainfall for this event was
measured in the Upper Keys with Key Largo measuring 2.48 inches of
rain, Florida Keys Marathon International Airport measuring 0.99
inches, and Key West International Airport measuring 0.73 inches.
No significant damage was reported with only minor street flooding
and isolated power outages being the biggest impacts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  93  83  92  83 /  30  30  30  30
Marathon  93  83  92  83 /  30  30  30  30

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 10 AM this morning to 7 PM EDT this evening
 for FLZ076>078.

GM...None. &&

$$

Public/Marine/Fire...NB
Aviation/Nowcasts....JAM
Data Acquisition.....JAM

Visit us on the web at weather.gov/key

Follow us on Facebook and Twitter at:
www.facebook.com/nwskeywest
www.twitter.com/nwskeywest