National Weather Service

Area Forecast Discussion
Issued by NWS Key West, FL

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389
FXUS62 KKEY 180728
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
328 AM EDT Tue Jun 18 2024

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

.DISCUSSION...
-- Changed Discussion --Issued at 328 AM EDT Tue Jun 18 2024

A not so quiet overnight for the Florida Keys as cloud streamers
with embedded showers have been moving along in a east-southeast
flow. Surprisingly, even though we had no inhibition, there was
not enough lift to allow for showers to achieve any lightning.
That being said, not all areas have seen showers and in fact most
of the activity has favored the Middle Keys and portions of the
Upper Keys. Recent radar trends would suggest that the Lower Keys
may see some showers prior to dawn. Strong surface high pressure
centered off the New England coast continues to work in tandem
with falling pressures over the Yucatan Peninsula and the Bay of
Campeche. This is maintaining fresh easterly breezes across the
island chain and surrounding waters. This is also keeping
temperatures in the lower 80s with dew points in the mid 70s.

.FORECAST...
The forecast thought process is a little more clear in the short
term but remains murky and complicated in the long term. For
today, the Keys will be in between features with no mid or upper
level support to lend to what we are already seeing develop. As a
result, showers will be isolated to scattered, developing in the
most healthy cloud streamers. By Wednesday a mid level short wave
will pivot southwest from the Atlantic and move across the Florida
Peninsula. At the same time, an easterly undulation will be
sliding westward. The combination of which will lead to a little
bit more lift but with a lack of a surface reflection.
Thursday, a surface reflection of an easterly undulation will
pass through the region but by this point the upper level support
will have shifted further southwest. As such, rain chances will be
held at 40 percent.

Thereafter there is still disagreements with the models as to how
features will interact with one another and where they will
eventually settle. Models are hinting that the Central American
Gyre (CAG) will produce another broad area of disturbed weather
northwestward across the Yucatan and into the southwest Gulf of
Mexico. As is the case currently, we will have to wait to see how
this new potential feature plays out. For now, given that it looks
like we`ll stay in generally easterly flow through the extended
period along with ample boundary layer moisture, have opted to
keep above normal PoPs.-- End Changed Discussion --

.MARINE...
-- Changed Discussion --Issued at 328 AM EDT Tue Jun 18 2024

Small Craft Advisories continue for all of the Florida Keys
coastal waters today. Strong surface high pressure centered off
the New England coast will continue to work in tandem with
falling pressures over the Yucatan Peninsula and the Bay of
Campeche. This is expected to result in moderate to fresh breezes
today through mid week. An area of low pressure may develop mid
week a few hundred miles north of the central Bahamas towards mid
week and move towards the north to central Florida coastline. This
may result in a slackening of breezes.-- End Changed Discussion --

.AVIATION...
-- Changed Discussion --(06Z TAFS)
Issued at 328 AM EDT Tue Jun 18 2024

VFR conditions will prevail at both EYW and MTH through the TAF
period. KBYX currently shows showers moving from southeast to
northwest, but it is difficult to say if any showers make it onsite
to either of the terminals. Will keep VCSH in the TAFs for now, but
TEMPOs may have to be added eventually to account for any
deteriorating conditions. Skies prevail at FEW at 2k feet, but
occasional instances of BKN at approximately 5k feet will transverse
both terminals.-- End Changed Discussion --

.CLIMATE...
-- Changed Discussion --In 1972, during the early morning hours, Tropical Storm Agnes passed
northward through the Yucatan channel. The outer rainbands of
Tropical Storm Agnes spawned at least three, to as many as six
tornadoes in the Florida Keys, including a F2 tornado in Big Coppitt
Key, a F2 tornado in Key West, and a F1 tornado in Conch Key. Total
damage was estimated at just over $500,000 (1972 USD). About 40
people were injured in Big Coppitt Key, making the Big Coppitt Key
tornado the worst in the history of the Florida Keys in terms of
total number of injuries.-- End Changed Discussion --

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --Key West 89 82 89 81 / 40 30 40 40
Marathon 89 82 89 81 / 30 30 40 40-- End Changed Discussion --

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.

Public/Marine/Fire...LIW
Aviation/Nowcasts....DP
Data Acquisition.....DP

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