Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
FXUS62 KKEY 040251

Area Forecast Discussion
National Weather Service Key West FL
951 PM EST Sat Dec 3 2016

.DISCUSSION...In the middle and upper levels(700-200 mb), latest
available IR satelitte imagery overlaid with model streamline
analysis as of 900 pm depict a still sharpening full latitudinal
trough oriented from Saskatchewan down to Southern Baja California.
Well downstream and to the southeast of that feature the center of
an expansive deep and warm middle and upper anticyclone was
positioned over the Western Caribbean Sea. South Florida and the
Florida Keys lie on the northern periphery of the deepest ridging
with water vapor imagery delineating very dry air.

At the surface and in the lower to middle levels,(Surface to 700 mb),
latest available marine and land surface observation and analysis
overlaid with IR satelitte imager as of 900 pm detail the axis of a
cool near 1030 mb surface ridge oriented from near Chicago to West
Virginia. Well to the south of that, a stubborn stationary frontal
boundary is analyzed in the Florida Straits just south of the Florida

.CURRENTLY...Skies as of 900 pm across the islands and adjoining
waters remain mostly cloudy owing too stratus and nimbostratus clouds
and rainshowers. Only a few sprinkles are occurring across the
islands with Key West radar showing us that most of the showers
associated with the stalled boundary remain to the immediate south of
the Florida Reef. Temperatures along the Reef are still in the humid
mid to upper 70s with dewpoints in the lower 70s. C-man stations
along the Florida Reef are registering northeast to east near 20
knots as well at Smith Shoal Light, and 15 to 20 knots in Florida
Bay. The evening sounding continued to illustrate a somewhat moist
fresh flow in lower to middle troposphere...with moisture in place from
the surface up to 750 mb.

.SHORT TERM...Overnight, a weak disturbance will track from west to
east across the Northern Gulf Coast. This feature, in tandem with
intensifying surface high pressure over the Ohio Valley and Mid-
Atlantic states will result in breezy conditions continuing across
the islands and surrounding waters. The weak convergence zone will
remain just south of the Middle and Lower Florida Keys overnight,
with only some sprinkles and maybe a brief light shower on the
northern side of this boundary reaching these islands. This will also
maintain a preponderance of lower clouds in and around the Keys as
well. But the drier air associated with the middle level ridging is
progged by the forecast soundings to seep down later across the
Keys, keeping only a slight chance for showers overnight. No changes
on this cycle.


.MARINE...Winds have come up as anticipated across all the waters to
near 20 knots, except 15 to 20 knots across Florida Bay. Will keep
the advisory going through the night, and likely through the day


.AVIATION...A stratus deck is forming across the northern FL Keys and extreme
southern FL with the cloud deck hovering just above 2kft. This deck
will likely linger through much of the terminal forecast period with
frequent flips between VFR/MVFR for EYW and MTH due to SCT/BKN
ceilings. Gentle to moderate breezes out of the east will continue
with higher gusts possible.


GM...Small Craft Advisory overnight for GMZ032>035-



Data Collection......DR

Visit us on the web at

Follow us on Facebook and Twitter at: is the U.S. government's official web portal to all federal, state and local government web resources and services.