Area Forecast Discussion
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000
FXUS62 KKEY 191854
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
254 PM EDT Sat Aug 19 2017

.DISCUSSION...
.CURRENTLY...
Under partly cloudy skies, temperatures are hovering around 90
degrees along the island chain. Meanwhile, local radars are
detecting isolated showers and an occasional lightning storm on
the nearshore and offshore waters south of the Florida Keys.
Surface wise, a weak ridge lies along the Sunshine State and the
adjacent coastal waters, while a tropical wave is located between
the Bahamas and Andros Island.

&&

.SHORT TERM...(Tonight through Tuesday night)
A tropical wave between Andros Island and the Bahamian chain will
migrate westward and across our region late tonight and Sunday
morning followed by a formidable low level easterly surge into
Monday. Given an increase in both moisture and low level
confluence, shower and thunderstorm activity will be on the
increase especially late tonight and into Sunday. Hence, well
above normal pops will be retained. Thereafter, a freshening and
deepening easterly flow on the southern periphery of an Atlantic
ridge axis to our north will result in middle of the road pops
on Monday. Another tropical wave will approach our area late
Monday night and pass through our region on Tuesday and Tuesday
night. Subsequently, above normal rain chances will be kept for
the first half of next week. Due to additional cloudiness and some
heavy downpours, high temperatures will average from the upper
80s to lower 90s with overnight lows from the mid 70s to the lower
80s.

&&

.LONG TERM...(Wednesday through Saturday)
With the western Atlantic ridge, weakening and sagging southward
from the Florida peninsula and into the Straits of Florida, a
slackening and a predominate southerly flow seems likely. With
plenty of moisture and the light to gentle winds, mesoscale
forcing in the form of wet cloud line genesis and boundaries
emanating off our large surrounding land masses will prompt middle
of the road pops. See no reason to stray from highs in the lower
90s with lows in the lower 80s.

&&

.MARINE...
Outside of showers, thunderstorms and outflow boundaries light to
gentle east winds will slowly increase tonight but especially
Sunday afternoon and night when a Small Craft Advisory/Exercise
Caution headline will likely be needed for most Keys coastal
waters.

&&

.AVIATION...
.Cloud lines along the Florida Keys warranted an initial vicinity
shower mention for Key West, otherwise VFR is expected to prevail
through the evening. Increasing chances for showers and
thunderstorms overnight into early Sunday have resulted in elevated
vicinity shower and eventual thunder for both Marathon and Key West
from roughly midnight through 18Z Sunday. As timing becomes more
defined, some temporary IFR visibilities in showers and
thunderstorms may be introduced. Surface winds for the remainder of
the day will be mainly northeast 5 to 10 knots, eventually becoming
east early Sunday and increasing closer to 10 knots. AVIATION...


&&

.CLIMATE...
In 1929, the daily record low temperature of 72F was last
recorded in Key West. Temperature records have been kept since
1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West 81 89 85 90 / 50 70 30 40
Marathon 81 92 85 93 / 50 70 30 40

&&

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

$$

Public/Marine/Fire...APA
Aviation/Nowcasts....Rizzo
Data Collection......DR

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