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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

FXUS62 KKEY 161951

Area Forecast Discussion
National Weather Service Key West FL
251 PM EST Fri Feb 16 2018

The deep mean-layer ridge remains parked over the Florida 
Peninsula. Water vapor imagery reveals a broad expanse of dry air 
over the Caribbean and Central America, in stark contrast to the 
lengthy plume of moisture reaching northeast from the Baja 
Peninsula to Nova Scotia. The surface ridge axis reaches west 
across South Florida, maintaining gentle to moderate, east to 
southeast breezes across the Florida Keys. Temperatures are near 
80, with dewpoints in the mid 60s. The KBYX radar is echo free. 

.SHORT TERM (Tonight through Sunday night)...
The mean layer ridge will flatten and shift to the northeast
tonight through Sunday. The resulting realignment of the low 
level steering will allow tropical east-southeasterlies to
effectively moisten the lower troposphere. Rain chances increase
somewhat Saturday night and Sunday, roughly correlated with a
meager moisture maximum currently east of the Bahamas (see 
GOES-16 derived TPW products). Temperatures will reach the lower 
80s through the short term, with overnight lows in the lower to 
mid 70s. Easterly winds will increase to near 15 knots along the 
Reef by Sunday. 


.LONG TERM (Monday through Friday)...
The mean layer ridge will consolidate into an impressive
anticyclone east of the Atlantic Bight Monday through Tuesday 
night. The surface high will broaden and strengthen over the
western North Atlantic, freshening east to southeast breezes
across the coastal waters. Weak undulations in the easterlies
accompanied by brief layers of deeper low level moistures will
increase rain chances Monday through Tuesday. Breezes will 
persist Thursday through Friday as the surface high retrogrades 
southwest. Meanwhile, the air mass will become less tropical as
the high approaches. 


No current watches, warnings, or advisories, although this may
change after this weekend. High pressure will prevail across the 
Florida Peninsula tonight through Sunday. High pressure will 
expand and strengthen across the western North Atlantic Monday 
through Wednesday. Small Craft Advisories likely will be required 
Sunday night through at least Wednesday night. 


Expect VFR conditions at the KEYW and KMTH terminals this evening
through Saturday morning. Easterly low level breezes between 5 
and 10 knots will turn to the northeast/east late this evening, 
then return to east around sunrise on Saturday. 


On this date in 1991, the low temperature in Key West dipped to 
53 degrees. This set the daily low temperature record for February
sixteenth in the city. Temperature records for Key West date back
to 1872. 


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




Aviation/Nowcasts/Data Collection....04

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