Area Forecast Discussion
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FXUS62 KKEY 212004

Area Forecast Discussion
National Weather Service Key West FL
304 PM EST Sat Jan 21 2017

Strong winds and high seas expected late Sunday night into Monday

Under golden sunshine and gentle south winds, temperatures are
ranging between 80 and 85 degrees along the Florida Keys.
Meanwhile, local radars are not detecting any precipitation
echoes but a large area of false echoes in the form of chaff is
covering our region. Surface wise, a western Atlantic ridge axis
is draped from the Bahamas across the Florida Straits and into the
Gulf of Mexico. Across our marine district, winds have slackened
from the earlier surge, with mostly south winds of 10 to 15 knots.

.SHORT TERM...(Tonight through Tuesday)
A deepening and intensifying southern stream trough will
translate slowly into the southeast United States and the Gulf of
Mexico on Sunday, before exiting into the western Atlantic ocean
on Tuesday. Given the strengthening large scale ascent associated
with significant positive vorticity advection and a powerful jet
streak, surface low pressure will intensify and move into the
Kentucky blue grass state with an an associated pre-frontal
trough draped southward into south central Gulf of Mexico. Amazing
medium range guidance has been incredibly consistent with the
timing of the pre-frontal trough moving into the coastal waters of
Fort Jefferson National Park at around 1 am, and then exiting east
of the Florida keys by 7 am. However, subtle changes are indicated
with the mid and upper level vorticity advection staying a little
further poleward over the last couple of model runs. Regardless,
enough moisture and strong momemtum with unidirectional southwest
boundary layer to 700 mb winds averaging between 45 and 55 knots.
Subsequently, locally strong to perhaps severe wind gusts are
possible with the aforementioned boundary. In wake of the trough,
strong west to northwest winds with patches of light rain and
temperatures holding in the lower to mid 70s are expected for the
balance of Monday. Additional cooler and drier air will seep into
our area through Tuesday with no precipitation expected.


.LONG TERM...(Tuesday night through Saturday)
A fairly tranquil and chamber of commerce type weather pattern can
be expected through at least Thursday night, before a possible cold
front passes through our area late Friday and Friday night. With
that said, it appears the majority of the mid and upper level
ascent will remain well north of our area with low level
confluence providing the best chance of measurable rainfall on
Friday. Near to slightly above normal temperatures may drop a tad
below normal temperatures in wake of the cold front.


Periodic wind surges and lulls will occur on our marine district
tonight and Sunday morning, before freshening south to southwest
winds overspread all Keys coastal waters into Sunday night through
Monday. Furthermore, a strong pre-frontal trough will be preceded
and accompanied by a swath of showers and embedded thunderstorms
some likely will be strong from west to east between 10 pm and
6 am. Hence, hazardous marine conditions can be expected late
Sunday night into Monday night.


Prevailing VFR is expected for EYW & MTH through the terminal
forecast period. Southerly gentle to moderate breezes will become
light and veer south-southeast for a brief window this evening,
before winds pick up significantly around between 3z/9z. Expect
moderate to fresh breezes out of the south Sunday, in advance of
an incoming cold front. &&

In 1971, the daily record low temperature of 46F was recorded in
Key West. Temperature records have been kept since 1872.


Key West  76  81  73  74 / 20 20 80 40
Marathon  76  85  72  76 / 20 20 80 40




Data Collection......Fling

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