763 
FXUS62 KKEY 300336
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
1036 PM EST Thu Dec 29 2022

...New DISCUSSION, MARINE, AVIATION...

.DISCUSSION...
Issued at 1036 PM EST Thu Dec 29 2022

Widely scattered light showers brought trace rainfall amounts to
some spots along the Keys island chain, including here in Midtown
Key West, earlier in the evening, but dry conditions prevail at
the moment with radar detecting only a few light showers well
south and southwest of the Lower Keys. Temperatures along the
island chain are mostly around 70 degrees, and winds on land
remain from the northeast to east around 10 mph.

Surface analysis depicts a large high pressure area centered near
Bermuda, with a ridge extending westward into the Southeastern
states. The Keys lie within a rather tight pressure gradient 
along the southern flank of this high. Although we continue to see
strong low level winds (31 knots at 1000 feet on the evening Key
West sounding), the influence of cooler Bay and Gulf side waters
is causing significant decoupling of surface winds along and 
north of the island chain. The measured PW of 1.53 inches with  
the evening sounding is close to the 90th percentile for this
date, but we continue to see significant dry layers in the lower
to mid levels along with a couple of weak inversions. These are
due to the continued presence of nearby lower and mid level
ridging across our region. MIMIC-TPW satellite imagery shows a 
swath of above normal moisture slowly lifting northward across the
area.

Overnight, we expect little change as partly cloudy skies will
continue with temps not dropping much more from their current 
readings. Although there is very little shower activity at the 
moment, will retain 20 percent PoPs through the night as showers 
will sometimes redevelop after midnight in these moderate to fresh
easterly flow patterns when sufficient moisture is available. Any
showers that do develop should remain light. Have updated the 
public forecast to lower overnight lows to around 70 based on 
evening temp trends, and to remove the wind transition as we have 
now decoupled. 

&&

.MARINE...
Issued at 1036 PM EST Thu Dec 29 2022

Evening observations show NE/E winds of 14 to 18 knots along the 
reef and at Smith Shoal Light, and 8 to 12 knots at Long Key Light
in Florida Bay, with seas at Satan Shoal Light running 4 to 5
feet. Small Craft Exercise Caution headlines will remain posted
for all marine zones except Florida Bay with the late evening 
forecast update. From the synopsis, moderate to fresh northeast to
east breezes late this evening will slacken somewhat late 
tonight, then expansive high pressure centered along the Mid- 
Atlantic coast will maintain gentle to moderate northeast to east 
breezes through the end of the week. The ridge axis will settle 
southward towards South Florida this weekend, resulting in 
slackening east to southeast breezes Friday night through Sunday. 
As an upper- level trough slides into the Midwest, east to 
southeast breezes will slowly freshen once again for early next 
week.

&&

.AVIATION...
(00Z TAFS)
Issued at 1036 PM EST Thu Dec 29 2022

VFR conditions will prevail through Friday at the EYW and MTH
terminals. Isolated showers will be possible overnight into Friday
morning, but the potential for any significant impacts at either
terminal is very low. Surface winds will remain from the
northeast to east at 6 to 12 knots.

&&

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

$$

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

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