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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

FXUS62 KKEY 170903

Area Forecast Discussion
National Weather Service Key West FL
403 AM EST Sat Feb 17 2018

Another benign February overnight with mostly clear to partly 
cloudy skies with only a few light showers migrating westward on 
the outer Straits of Florida beyond 20 nm from the island chain. 
With light mostly east winds, temperatures are hovering in the 
lower 70s in most Keys communities. Surface wise, a modest western
Atlantic ridge extends across a good portion of the Florida 
peninsula and reaches well into the Gulf of Mexico. On our coastal
waters, winds are northeast to east ranging from 3 knots at 
Carysfort Reef Light to 11 knots at Alligator Reef Light. 


.SHORT TERM...(Today through Monday night)
The persistent deep, east-west oriented ridge axis lying across
the Sunshine State and the adjacent Gulf and Atlantic Ocean will
slowly lift northward over the next couple of days. With the ridge
axis moving away, our region will lie on the southern portion of
the anticyclonic flow. Although mid and upper level descent will
predominate, periodic pockets of higher moisture along with
increasing low level confluence will prompt mainly isolated 20 
percent pops starting tonight. However, between these patches of
higher moisture, drier air below 700 mb will likely result in
spells of little if any precipitation so timing will be tricky.
High temperatures will average in the lower 80s with lows in the
lower to mid 70s.  


.LONG TERM...(Tuesday through Friday)
The deep and massive tropospheric western Atlantic anticyclone 
will remain aligned across the extreme southeast United States
before slowly settling back down into the Florida peninsula during
the second half of next week. Because of this, large scale
synoptic descent will prevail but with pockets of higher moisture
passing through our region through most of the week. Given timing
uncertainty, rain chances will likely range between 10 and 30
percent through the period. High temperatures will average in the
lower 80s with overnight lows generally in the lower to mid 70s
which will be above normal. 


Light to moderate east winds will predominate on all Keys coastal
waters today and tonight before freshening Sunday with fresh to
strong easterly winds overspread our entire marine district Sunday
night and well into next week. With this wind increase, a Small
Craft Advisory will likely be required for most of our coastal
waters beginning Sunday night. But as usual, typical surges and
lulls can be expected.


Through 18/00Z, VFR conditions are expected to continue at the KEYW 
and KMTH terminals. Light northeast to east breezes 5 knots or less 
early this morning are expected to become east to southeast 5 to 8 
knots by afternoon.


In 1996, the daily record low temperature of 46 degrees was 
recorded in Key West. Temperature records have been kept since


Key West  80  72  80  72 / -  20 20 10 
Marathon  82  73  82  73 / -  20 20 10 




Data Collection......Rizzo

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