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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

                            
000
FXUS62 KKEY 211354
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
954 AM EDT Mon May 21 2018

.DISCUSSION...
.CURRENTLY...
KBYX is down for maintenance. KAMX detects scattered showers
throughout the forecast area. Skies over the island chain are
mostly cloudy. Winds over land are east to southeast near 15 mph.
C-MAN winds, on average, are east to southeast at 15 to 20 knots.
Temperatures are in the lower 80s.

.SHORT TERM (This afternoon)...
In the low levels of the atmosphere, a trough of low pressure will
be located over the northeastern Gulf of Mexico this afternoon. In
the mid to upper levels of the atmosphere, an area of low pressure
will be centered over the panhandle of Florida today. The 12z KKEY
sounding is moderately unstable and exceptionally moist, with a 
precipitable water (PWAT) value just under two inches. Atmospheric
moisture will increase this afternoon. By sunset this evening, 
PWAT values will be just above two inches, which is near the 90th 
percentile for the latter half of May. Cyclonic flow in all levels
of the atmosphere, coupled with an extremely moist and unstable
air mass in place, will be responsible for rain chances today well
beyond normal for this time of year. 

&&

.MARINE...
A Small Craft Advisory is in effect for the coastal waters of
Florida Bay, the nearshore Gulf of Mexico, and Atlantic this
afternoon due to sustained east to southeast winds near 20 knots.
A Small Craft Advisory will likely be required for all Keys
coastal waters tonight and Tuesday. A Small Craft Advisory will
likely be required for the coastal waters of the Florida Straits
Tuesday night. A Small Craft Advisory may be required for the
coastal waters of the Gulf of Mexico and Hawk Channel Tuesday
night. No advisories expected Wednesday through at least Thursday.
A Small Craft Advisory may be required for the coastal waters of
the Florida Straits Thursday night. A Small Craft Advisory may be
required for all Keys coastal waters Friday and Friday night.

&&

.AVIATION...
MVFR conditions accompanying shower/thunderstorm activity will 
remain possible through 22/12z at EYW and MTH. Expect
southeasterly winds sustained near 12 knots, with gusts near 20 
knots, through the terminal forecast period. 

&&

.CLIMATE...
On this date in Keys Weather History, in 1929, the daily record 
rainfall of 3.54 inches was recorded in Key West. With a high chance 
of rain today, there is a very slim probability for this record to 
be broken. Precipitation records for Key West date back to 1871. 

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ031-032-035-042>044-052>055-072>075.

&&

$$

Public/Marine/Fire...BS
Aviation/Nowcasts....MCLOVIN
Data Collection......BT

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