Area Forecast Discussion
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FXUS62 KKEY 230838
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
438 AM EDT Mon Apr 23 2018

.DISCUSSION...
.CURRENTLY...
Under mostly clear skies and light to gentle southeast winds,
temperatures are primarily in the upper 70s along the island
chain. Meanwhile, local radars are only detecting a few showers on
near the Upper Keys and into nearshore and offshore waters
southeastward out 60 nm. Surface wise, a low pressure system
(1007 mb) is located over western Tennessee with a trough
extending southward into the east central Gulf of Mexico, while
high pressure is centered along the Mid Atlantic coast. On our
marine district, winds are southeast ranging from 11 knots at
Sombrero Key Light to 14 knots at Carysfort Reef Light.

&&

.SHORT TERM...(Today through Wednesday night)
Surface low pressure over the Tennessee valley will slowly become
concentrated and strengthen somewhat, as it moves up the Eastern
Seaboard by the middle of this week. With the progression of this
low pressure system, a nebulous trough will likely pass through
our region but with mid and upper level lift remaining well north
of our region Tuesday night and Wednesday. Until then, light
winds with limited moisture will pose a significant challenge for
the potential of wet cloud line genesis today and Tuesday, along
with a light steering flow tonight. Subsequently, only isolated
dime pops will be inserted for the island chain until generous 30
percent pops are retained for Tuesday night. Thereafter, weak high
pressure will nose into our area from the Gulf of Mexico
resulting in only dime pops again. Temperatures will remain above
normal with daytime highs in the mid to upper 80s and overnight
lows in the mid to upper 70s.

&&

.LONG TERM...(Thursday through Sunday)
Despite a deepening mid and upper level trough setting up over the
Eastern United States, our area will remain on the extreme
southern periphery of a cyclonic flow with the main ascent aloft
remaining poleward. Within this trajectory, a couple of weak
areas of low pressure are expected to form along the Southeast
United States and the Carolina coast before lifting rapidly
northeastward, resulting in a weak and chaotic surface flow in
our region. Subsequently, only 10 to 20 percent pops which are a
blend of the ECE/MEX 12 hour pops will be kept through the period.

&&

.MARINE...
Light to gentle southeast winds today will decrease and become
light tonight before turning south to southwest near 10 mph or
less on Tuesday afternoon. Winds will clock around to northwest
to north before turning westerly during the end of this week,
hence, no headlines will be needed.

&&

.AVIATION...
VFR conditions will prevail at EYW and MTH through at least the next
24 hours. Brief, MVFR ceilings, based at around 1,500 feet, are
conceivable at EYW and MTH late tonight and Monday morning. This
possibility is not great enough to place in the terminal forecasts
at this time. Sustained southeast winds near 15 knots from just off
the surface to about 3,000 feet will decrease to near 10 knots
Monday morning.

&&

.FIRE WEATHER...
No rainfall is expected today but relative humidity values will
remain above 60 percent with mostly southeast to south winds of 10
mph or less at Big Pine Key. Winds will slacken further with
little chance of measurable rainfall tonight and on Tuesday.

&&

.CLIMATE...
In 1940, the daily record low temperature of 62 degrees was
recorded in Key West. Temperature records date back to 1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  85  77  84  75 / 10 10 10 30
Marathon  87  78  87  76 / 10 10 10 30

&&

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

$$

Public/Marine/Fire...APA
Aviation/Nowcasts....BS

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