000
FXUS62 KKEY 201921
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
321 PM EDT Thu Sep 20 2018

.DISCUSSION...
Currently - Weak high pressure across South Florida is in the
process of being reinforced by another ridge building southward
along the Atlantic coast. In the meantime, day time heating over
South Florida has resulted in light and variable winds across the
Florida Keys. A light northerly steering flow along with a bit of
inhibition has prevented showers from developing along an island
cloud line this afternoon. Shower and thunderstorm activity is
however creeping southward off of South Florida into the Florida
Bay and Upper Keys.

Forecast - Light and variable winds this evening will become more
defined out of the east tonight as high pressure to our north
continues to be reinforced. Until then, light north to
northeasterly flow will direct convection originating over South
Florida into the Keys and the island cloud line will continue to
try to hang on and try to activate. For this reason a 30 to 40
percent pops is justified for tonight.

Ridging over the southeastern United States will then maintain
light to gentle east breezes across the Keys this weekend.
Meanwhile, an upper level low will retrograde southwestward across
South Florida into the Gulf of Mexico through this period. There
is a subtle hint of an associated lower level reflection pulling
across our area. Guidance continues to suggest high chance pops.
These factors support maintaining somewhat above normal pops
through the weekend. Expect near normal highs and lows.

Through the first half of the upcoming week another deep layered
low will migrate westward from the North Atlantic towards the
Florida coast, before being quickly absorbed by a mid latitude
trough. At this point, this feature will be too far north to
directly affect Keys weather other than dampening our flow. Will
maintain near normal temps and pops through the extended.

&&

.MARINE...
Ridging building down the Atlantic coast is in the process of
reinforcing a ridge across South Florida. As a result, light and
variable winds will become easterly and gradually and only
moderately strengthen over the next couple of days. No cautions or
advisories are anticipated at this time.

&&

.AVIATION...
VFR conditions will prevail at both EYW and MTH terminals.
Showers and thunderstorms will develop over the mainland and may
move into the region late this afternoon and evening affecting
primarily MTH, and later possibly EYW. Brief MVFR ceilings and IFR
to MVFR visibility reductions are possible with passing showers
and thunderstorms. Wind will be light and variable this afternoon
and overnight, becoming light east tomorrow morning.

&&

.CLIMATE...
On this date in 2005, Hurricane Rita passed south of the Keys.
Key West International Airport recorded maximum sustained winds of
62 mph and gusts of 76 mph. Marathon Airport recorded maximum
sustained winds of 41 mph and gusts of 52 mph. Storm tides in the
Florida Keys were generally 3 to 5 feet above mean sea level.
Numerous streets throughout the Lower Keys were completely
impassable due to storm surge flooding, and at least 200 homes
were flooded in Key West.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  90  83  91  81 / 30 30 40 50
Marathon  91  82  92  80 / 30 30 40 50

&&

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

$$

Public/Marine/Fire...11
Aviation/Nowcasts....Chesser
Data Collection......SDR

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