700 
FXUS62 KKEY 211911
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
311 PM EDT Sat Aug 21 2021

.DISCUSSION...
A fractured low-level ridge axis stretches west across Florida. 
Gentle east to southeast breezes prevail across the Florida Keys, 
with mostly sunny skies and temperatures near 90. The KBYX radar 
detects isolated showers and thunderstorms moving across the
island chain. There is very little activity behind this broken
line of showers, related to a dry air sliver noted on MIMIC TPW 
products.

.FORECAST...
Mean layer ridging will stretch west across Florida throughout the
forecast period. Moderate breezes will freshen somewhat Monday
night and Tuesday as the Bermuda High stretches over the western
North Atlantic. Breezy conditions will last through at least
Wednesday night. Rain and thunder chances will be dictated by 
undulations in moisture sliding along the southern flank of the 
subtropical ridge. One such undulation will move through the Keys 
tonight and Sunday morning, and we have nudged PoPs up to 40% to 
account for this moisture slug. Split difference products place 
the leading edge of a large SAL plume moving into the southeastern
Bahamas. Forecast soundings place the peak of this plume across 
the Keys on Monday and Monday night, as such we introduced some 
haze into the derived weather products. Also, the MOS consensus 
indicates only slight rain/thunder chances Sunday night through 
Monday night as the SAL approaches and moves through the area.
Thereafter, we have retained near normal rain/thunder chances
(~30%) as the ridge remains entrenched across Florida. The long
range prognostics indicate a developing Central American Gyre,
which will result in poor run to run consistency, and spurious
lows rotating around the large gyre. The preseason is now over,
and the peak of hurricane season is not until September 10th.  

&&

.MARINE...
There are no watches, warnings, or advisories currently in effect
for the coastal waters of the Florida Keys. High pressure 
extending from the Western Atlantic across the Florida Peninsula 
will maintain moderate east to southeast breezes tonight through 
Monday. Breezes will freshen Monday night and Tuesday as the 
Bermuda High matures.

&&

.AVIATION...
VFR conditions prevail at both EYW and MTH for the remainder of the 
day through tonight. VCSH was introduced at both terminals due to a 
brief line of isolated showers sliding in from the southeast. Little 
precipitation is expected after their passage this evening. East 
winds around 10 knots persist into the night.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  82  89  82  91 / 40 40 20 20 
Marathon  81  91  83  93 / 40 40 20 20 

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&

$$

Public/Marine/Fire...CLR
Aviation/Nowcasts....K. Kuyper/JAM
Data Acquisition.....KR

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