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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

FXUS62 KKEY 241931

Area Forecast Discussion
National Weather Service Key West FL
331 PM EDT Thu May 24 2018

Weak shower coverage has gradually across the western Florida 
Straits, and a few isolated cells have propagated across the 
Middle and Upper Keys this afternoon, but only a few lightning 
strikes have occurred in our far western forecast domain thus far
today. IR/Differential Water Vapor/MIMIC imagery indicates a 
steady moistening air mass out of the southwest, near a surface 
low just east of the Yucatan Peninsula that continues to become 
better defined. The 2pm Special Tropical Weather Outlook from the 
NHC has indicated a high chance of tropical or subtropical 
development through 48 hours (80%), as well as through 5 days 

Temperatures across the island chain range from 81 in cloud cover to
87 in peaks of sun, with dew points holding steady near the mid
70s. Across our marine district, winds are east at 10-15 knots.

A wet pattern remains in place across the Florida Keys and most of
the state and southeast US as all eyes remain on the disturbance
east of the Yucatan. The system is forecast to remain somewhat
stationary before shifting northward Friday night, emerging into
the southern Gulf of Mexico Saturday, shifting into the north-
central gulf Sunday into Monday. Primary impacts from the system
for the Keys, regardless of development, will be the potential 
for heavy rainfall and gusty winds (with isolated thunderstorms) 
into Memorial Day Weekend, Saturday and Saturday night under the 
greatest probability due to the proximity of the low during that 
time frame. WPC includes portions of the Keys in a Marginal 
Excessive Rainfall Risk for Friday and Saturday.

The tropical or subtropical system is expected to move into the
northern gulf coast Monday evening and into the southeast US
thereafter. However, the Bermuda High positioned to our east will
keep deep tropical moisture across the Florida Keys through at
least Tuesday. However, the high pressure ridge axis shifts
westward, and will drag a dry air mass to South Florida mid to
late next week... possibly putting an end to our highly anomalous 
synoptically wet pattern, just in time for the official start of 
hurricane season.


No watches, warnings, or advisories are currently in place across
the coastal waters surrounding the Florida Keys. Small Craft
Advisory conditions may be possible Friday Night, lasting into the
holiday weekend. 


VFR conditions are expected at both the Key West and Marathon 
terminals through this evening and overnight. There is a chance of a 
passing shower which may bring brief periods of MVFR conditions. 
Near surface winds will be mainly from the east between 5 and 10 
knots, increasing to near 15 knots after sunrise Friday.

Key West  76  82  75  81 / 50 60 60 80 
Marathon  76  85  76  84 / 50 60 60 80 




Data Collection......BT

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