Area Forecast Discussion
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FXUS62 KKEY 220804
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
404 AM EDT Mon Oct 22 2018

.DISCUSSION...
.CURRENTLY...
Skies vary from mostly cloudy from Key West to near Marathon, to
mostly clear to partly cloudy elsewhere. Outside of rainfall,
temperatures are averaging in the upper 70s in most of the island
chain. Meanwhile, local radars are detecting scattered showers
along the Lower Keys and the adjacent nearshore waters. In
addition, additional showers are affecting the offshore waters of
Mainland Monroe. Movement of most activity is toward the west at
10 to 15 knots. Surface wise, a trough of low pressure associated
with the shower activity is draped over the Lower Keys and the
adjacent Gulf and Straits of Florida. On our marine district,
winds are northeast to east averaging near 15 knots.

&&

.SHORT TERM...(Today through Wednesday night)
An expansive region of high pressure over the eastern United
States and down the Sunshine State will slide quickly eastward
into the western Atlantic Ocean tonight and further offshore
through the middle of the week. Meanwhile, a trough of low
pressure associated with a brief wind surge and higher moisture
over the Middle and Upper Keys and the adjacent waters will sag
southward before stalling near our region through tonight.
Thereafter, this trough will lift northward as a low pressure
begins to take shape in the extreme northwest Gulf of Mexico
Wednesday night. With the close proximity of the trough, low
level confluence along with ample moisture below 700 mb will
prompt low chance pops through Tuesday night. In addition, enough
insolation, moisture and an increasing favorable low level wind
profile may allow wet cloud line genesis, especially along the
Lower Keys. Thereafter, a deepening troposheric anticyclone will
build over the eastern United States and the Florida Peninsula
resulting in large scale descent and lower moisture. Hence, only
isolated pops will be retained for the middle of this week.
Meanwhile, high temperatures will average in the mid to upper 80s
with overnight lows in the upper 70s.

&&

.LONG TERM...(Thursday through Sunday)
The aforementioned deep layered anticyclone will be squelched
southward in response to a trough digging down the Southeast
United States and down the Sunshine State by the end of this week
and weekend. Because of the progressive and equatorward extent of
the cyclonic trajectory, the first in a series of cool fronts will
approach our area Saturday and possibly pass through our region
Saturday night. A secondary weak cold front will likely approach
and pass through our region late Sunday or Sunday night. But until
this weekend, large scale subsidence and limited moisture should
keep rain chances in the slight category until low level
convergence and perhaps weak large scale ascent are the impetus
for chance pops this weekend. Above normal temperatures will
persist through at least Saturday, before gradual cooler and
drier air filters in.

&&

.MARINE...
Moderate to occasional fresh breezes can be expected on Keys
coastal waters today and tonight, before slackening appreciably
for Tuesday afternoon through Thursday. Thereafter, winds will be
on the increase ahead of an approaching cold front which may cross
our marine district late Saturday or Saturday night.

&&

.AVIATION...
Increased moisture and a gusty east northeast breeze along a
decaying frontal boundary will bring an uptick in SHRA coverage
over the next 24 hours. Given the uncertainty in timing and
coverage, will maintain VCSH at this time.

&&

.CLIMATE...
In 2008, the daily record rainfall of 7.30 inches of rainfall was
recorded in Key West. Temperature records date back to 1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  85  79  86  76 / 30 30 30 30
Marathon  85  79  86  77 / 30 30 30 30

&&

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

$$

Public/Marine/Fire...APA
Aviation/Nowcasts....Ulrich
Data Collection......99

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