Area Forecast Discussion
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FXUS62 KKEY 131849

Area Forecast Discussion
National Weather Service Key West FL
249 PM EDT Sun Oct 13 2019

High pressure centered east of the Atlantic Bight supports
moderate to fresh easterly breezes across the Florida Keys marine
district. Satellite derived moisture products indicate plenty of
tropical moisture (PW ~2.0") to the west of the Florida Keys, with
drier, more continental air advecting into the Bahamas. The KMFL
and MYNN 12Z soundings sampled much drier air than our KKEY
launch, corroborating the drier air upstream.

Temperatures this afternoon reached the upper 80s with dewpoints
in the mid 70s. Despite the higher humidity, the discerning local
can feel the decreased afternoon highs and the lower sun angle.
Very little rain and thunder coverage this afternoon, although the
most recent KBYX scans reveal convective temperatures have been
reached, with showers forming within the lee-side cumulus

The mean-layer ridge over the western Gulf of Mexico will control
the weather through the next several days as it lumbers to the
east, then southeast to near Cuba. The low level ridge axis
initially across north-central Florida will sag southward in
tandem with the upper ridge`s trek towards the Western Caribbean.
Rain chances and breezes will trail off tonight and Monday, as
the low level ridge axis approaches the Keys, dragging some of the
drier air south. Mesoscale processes will still be possible
Monday through Wednesday, so we have leaned a little above the MOS
consensus for rain chances. The subsidence aloft should prevent
deep convection from forming along the island chain. For Thursday
through Sunday, lower heights across the Gulf of Mexico and the
return of east southeasterly breezes should reinvigorate rain
chances across the Keys.


Small Craft Should Exercise Caution for east winds 15 to 20 knots,
which should trail off overnight. From synopsis, high pressure
will persist over the western North Atlantic tonight through
Tuesday. A weak pressure pattern will prevail across the Florida
Keys Tuesday night through Thursday night.


VFR conditions are expected at both EYW and MTH island terminals
through this evening. With relatively drier air moving into the
Florida Keys, expecting only a few isolated showers through 06z
along the island chain. The chances are too low to include any
mention of VCSH in the TAFs at this time. Winds will generally be
from the east at around 10 knots.


Key West  79  87  79  88 / 30 20 20 10
Marathon  79  88  79  89 / 30 20 20 10


FL...Coastal Flood Advisory for FLZ076.



Data Collection......KBL

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