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Area Forecast Discussion (AFD)

Issued by Key West, FL (KEY)

FXUS62 KKEY 171536

Area Forecast Discussion
National Weather Service Key West FL
1036 AM EST Sat Feb 17 2018

An upper-level composite analysis this morning reveals a
persistent deep layer mean anticyclone dominating large-scale
atmospheric flows across the entire region. The system was
centered over the western North Atlantic, with an associated
surface high pressure cell extending westward over the Florida
Peninsula and Gulf of Mexico. A light to gentle easterly flow
prevails at the surface across the Florida Keys and adjacent
coastal waters. The resident air mass is nearly maritime tropical,
with current air temperatures near 80F and dewpoint temperatures
in the upper 60s. Data from the Key West morning radiosonde
balloon indicated a very dry and stably stratified atmosphere,
with a strong subsidence inversion layer based just above 5000
feet elevation. Not surprisingly, local Doppler radar base 
reflectivity scans are void of precipitation.

Forecast updates are unnecessary this morning. Air temperatures
will be about five degrees F above average, with mostly sunny and
rain-free conditions.

No watches, warnings, or advisories are in effect for Florida 
Keys coastal waters. Light to gentle breezes from the northeast
through southeast will prevail this afternoon.

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.



Data Collection......CLR

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