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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

                            
085 
FXUS62 KKEY 190931
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
431 AM EST Mon Feb 19 2018

.DISCUSSION...
.CURRENTLY...
Under variably cloudy skies and light east winds temperatures are
in the lower to mid 70s along the island chain. Meanwhile, local
radars are detecting isolated showers on the Straits of Florida
southeast of the Middle and Upper Keys. Surface wise, an expansive
ridge of high pressure is aligned along the entire eastern
seaboard, and down the Sunshine State and into the Gulf of Mexico.
On our marine district, winds are east ranging from 13 knots at
Smith Shoal Light to 17 knots at both Pulaski Shoal Light and
Carysfort Reef Light and slightly higher southward. 

&&

.SHORT TERM...(Today through Wednesday night)
Without question, the combination of upglide below 700 mb, and 
strong low level confluence and moisture flux will provide the 
best chance for measurable rainfall along the Florida Keys
tonight, hence, 60 percent pops which is well above climo will be
inserted. Otherwise, subtle and occasional patches of low level 
moisture (below 850 mb) will pass through our region. Given timing
uncertainty, see no reason to stray from nickle to 20 percent 
pops through the period. Above normal temperatures will persist 
with daytime highs averaging in the lower 80s and overnight lows 
in the lower to mid 70s. 

&&

.LONG TERM...(Thursday through Sunday)
A deep layered Western Atlantic ridge axis extending across north
Florida will gradually sag southward and lie across extreme south
Florida, our region, and the adjacent northwest Bahamas and into
the southern Gulf of Mexico by Sunday. Given the position of the
large scale high pressure system, large scale subsidence will
strengthen resulting in lower moisture content through the period.
Regardless, the probability of precipitation will vary from nickle
to perhaps 20 percent pops. High temperatures will hover around 80
degrees with overnight lower in the lower 70s, to near 70 degrees
when winds abate next weekend. 

&&

.MARINE...
A Small Craft Advisory will remain in effect on the Straits of
Florida, with an Exercise Caution headline elsewhere. However, 
expect a fairly substantial wind surge to overspread our entire 
marine district tonight when a Small Craft Advisory will likely be
required for all keys coastal waters. Thereafter, typical wind 
surges and lulls will result in fresh to strong east to southeast 
winds to prevail with the highest winds on the Florida Straits and
the Reef Tract for most of this week. 

&&

.AVIATION...
Intermittent MVFR ceilings and shower impact will gradually 
becoming more of a probability today at EYW & MTH, with 9z-14z 
having the best initial chance. Easterly winds of 8-10 knots will 
increase to near 15 knots later this afternoon, packing gusts as 
high as 25 knots as winds veer to the east-southeast. 

&&

.CLIMATE...
In 1996, the daily record low temperature of 50 degrees was 
recorded in Key West. Temperature records date back to 1871. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West 81 74 81 75 / 20 60 10 - 
Marathon 83 74 83 75 / 20 60 10 - 

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ052>055-072>075.

&&

$$

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

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