964 
FXUS62 KKEY 070232
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
932 PM EST Sat Feb 6 2021

.DISCUSSION...
Earlier mid level clouds and scattered showers have shifted north
and east of the Keys this evening, leaving behind mostly clear
skies and dry conditions along the island chain. Radar detects
only isolated small showers north and west of the Dry Tortugas at
this time. Temperatures are hovering in the lower 70s, and winds 
on land are from the southeast at 5 to 10 mph. Surface analysis 
depicts a stationary front across central Florida and the northern
Gulf of Mexico, with developing low pressure along the front just
south of the western Florida panhandle. Aloft, water vapor 
imagery shows a shortwave trough moving east across Arkansas, 
while flat ridging is suppressed south and east of our area into 
the Caribbean. The 00Z Key West sounding found a surface-based 
inversion, with another inversion near 10K feet, and most of the 
column moisture confined below the mid level inversion. The very 
dry airmass still in place above 700 mb is reducing the impact of 
the otherwise unseasonably moist PW value of 1.59 inches. MIMIC- 
TPW imagery shows an area of somewhat lower PW values moving 
northward across the Straits and toward the Keys. 

Rain chances and winds are the main forecast problems for the rest
of the night. Radar/satellite trends this evening do not appear
favorable for much shower activity during the next several hours,
and almost all of the CAM guidance keeps the Keys largely dry
through daybreak. Although the 00Z sounding measured strong winds
of 24-33 knots just off the deck in the 1000-3000 foot layer, the
surface-based inversion has prevented these winds from mixing 
down so far. Winds are forecast to become southerly and increase
overnight, as the surface low strengthens and tracks across the NE
Gulf and North Florida, but confidence in this is not high. Have
updated the forecast to reduce rain chances to 20 percent and
remove mention of thunder throughout the Keys overnight, with
winds still forecast to increase somewhat before morning. 

&&

.MARINE...
Evening observations show gentle SE breezes around 10 knots across
the Keys waters. These winds are still expected to become S and
increase to around 15 knots during the next several hours across
much of the area. No advisories or headlines are anticipated for
the overnight, and only minor adjustments are planned for the late
evening forecast issuance.

&&

.AVIATION...
VFR conditions will prevail overnight and Sunday at the EYW and
MTH terminals. While short periods of MVFR ceilings cannot be
ruled out, mainly during the predawn and early morning hours, the
probability is too low to mention in the TAFs at this time. There
is some uncertainty as to how much winds may increase late
tonight. The current forecast calls for SE winds of 5 to 10 knots
to become S around 10 knots with gusts close to 20 knots late
tonight into Sunday, then become SW and decrease during the mid to
late afternoon hours. This wind forecast is lower confidence than
usual, and expect amendments as necessary.

&&

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

$$

Public/Marine/Fire...Jacobson
Aviation/Nowcasts....Jacobson
Data Acquisition.....JAM

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