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GMZ031 Florida Bay Including Barnes Sound, Blackwater Sound, And Buttonwood Sound- 431 Am Est Tue Dec 5 2023
Today..North to northeast winds 10 to 15 knots, becoming northwest to north and decreasing briefly to 5 to 10 knots in the afternoon. Bay waters a light to moderate chop, becoming smooth to a light chop. Isolated showers.
Tonight..Northwest to north winds near 10 knots, increasing to near 15 knots after midnight. Bay waters a light chop, becoming a moderate chop.
Wednesday..Northwest to north winds 15 to 20 knots, briefly decreasing to near 15 knots in the afternoon. Bay waters choppy, becoming a moderate chop.
Wednesday night..North to northeast winds 15 to 20 knots. Bay waters choppy.
Thursday..Northeast winds near 15 knots. Bay waters a moderate chop.
Thursday night..East winds near 15 knots. Bay waters a moderate chop.
Friday..East to southeast winds near 15 knots. Bay waters a moderate chop. Isolated showers.
Friday night..East to southeast winds 15 to 20 knots. Bay waters choppy. Isolated showers.
Saturday..East to southeast winds near 15 knots. Bay waters a moderate chop. Isolated showers.
Saturday night..East to southeast winds 15 to 20 knots. Bay waters choppy. Isolated showers.

GMZ005 Synopsis For Keys Coastal Waters From Ocean Reef To Dry Tortugas 431 Am Est Tue Dec 5 2023
Synopsis..Gentle to moderate northerly breezes are developing across the florida keys coastal waters this morning in the wake of an ongoing weak frontal passage. A second, much stronger cold front will push through the coastal waters late tonight or early Wednesday, with fresh northerly breezes expected in its wake. Strong high pressure will slide across the southeastern united states into the western north atlantic Friday through Saturday resulting in fresh easterly breezes.
the approximate shoreward edge of the gulf stream as of december 05...
56 nm south of dry tortugas light...on loggerhead key. 20 nm south of cosgrove shoal light...off the marquesas keys. 15 nm south of sand key light...off key west. 17 nm south of looe key...off big pine key. 20 nm south of sombrero key light...off marathon. 12 nm southeast of alligator reef light...off islamorada. 9 nm southeast of molasses reef light...off key largo. 2 nm east of carysfort reef light...off ocean reef.
gulf stream information courtesy of the naval oceanographic office.

FXUS62 KKEY 051052 AFDKEY

Area Forecast Discussion National Weather Service Key West FL 552 AM EST Tue Dec 5 2023

New DISCUSSION, MARINE, AVIATION

DISCUSSION
Issued at 550 AM EST Tue Dec 5 2023

Finally the effects of a weak frontal passage is being felt as a subtle air mass change is overtaking the Florida Keys this morning. Winds, which were light and variable, have quickly picked up to near 10 mph across the island chain with 10 to 15 knots being reported at most of our marine platforms. Dew points have also fallen a few degrees. Looking upstream dew points range from near 50 to upper 60s degrees. This air mass will modify as it moves across the waters and our dew points will not see as drastic of a fall as the mainland. A secondary front is still present to our northwest, which stretches across the Gulf of Mexico and over the Florida Peninsula. This front is slowly marching southward.

FORECAST
Forecast remains on track in the short term. This first frontal boundary moving through will bring lower dew points and slightly cooler temperatures for today. Confidence is low on today's dew points. Hi-res guidance shows dew points, especially in the Lower Keys tanking into the lower 50s. This seems extreme given how much modification should occur, however, given a wind direction off the mainland this morning, it is not totally out of the realm of possibilities. That said, will lean on the more optimistic side of values and will monitor through the day for any required changes.
High temperatures will be a few degrees cooler today compared to yesterday but daytime highs will still be in the lower 80s.

The aforementioned secondary front will push through the region late tonight into early Wednesday morning. This front will usher in a more appreciable air mass change with much cooler temperatures and much drier air. Daytime highs will fall comfortably into the lower to mid 70s with dew points ranging from the mid 40s to mid 50s across the island chain. Similarly, overnight lows will fall into the 60s with the Upper Keys possibly falling a hair below 60 degrees. In addition to the temperatures and humidity, winds will increase noticeably. Expect breezy conditions to quickly develop in the wake of the front. Strongest winds will occur Wednesday night before slowly tapering back through the rest of the week. The reason for a gradual slackening of winds is due to a relatively strong high pressure that will move in across the southeast U.S. behind the front. This will maintain at least moderate to fresh easterly breezes through the first half of the weekend.

The second half of the weekend and beyond remains questionable.
GFS which had shown a pronounced front blasting through the region has backed off significantly from yesterday. That being said, a front is poised to move through either Sunday or Monday but it may not be as strong as previously thought. Nonetheless, the dynamics are still there that thunder cannot be ruled. In fact, confidence is gradually increasing that we may need to introduce at least slight chance for thunderstorms on Sunday. Given the differences in timing and strength that are still present between the GFS and ECMWF, will hold off mentioned thunder in the actual forecast for at least one more full package.

MARINE
Issued at 550 AM EST Tue Dec 5 2023

Gentle to moderate northerly breezes have developed across the Florida Keys coastal waters this morning in the wake of an ongoing weak frontal passage. A second, much stronger cold front will push through the coastal waters late tonight or early Wednesday, with fresh northerly breezes expected in its wake. Small Craft Advisory conditions are possible, primarily Wednesday night but confidence remains low at this time. Thereafter, strong high pressure will slide across the Southeastern United States into the western North Atlantic Friday through Saturday resulting in moderate to fresh easterly breezes.

AVIATION
(06Z TAFS)
Issued at 550 AM EST Tue Dec 5 2023

A weak frontal boundary just moved through the island chain, bringing brief sub-VFR CIGS and wind increase to both terminals.
These lowered CIGS will gradually clear out and VFR conditions are expected through the TAF period. Surface winds will be from the north to northeast between 7 and 13 knots, with occasional to frequent gusts near 20 knots tonight.

CLIMATE

On this day in 1876, both the daily record cold high temperature of 60 F and the daily record low temperature of 45F were recorded in Key West. Temperature records date back to 1872.

PRELIMINARY POINT TEMPS/POPS
Key West 81 69 75 63 / 10 10 10 0 Marathon 82 67 74 62 / 10 10 10 0

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

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Alligator Reef Light
Click for Map
Tue -- 12:09 AM EST     Moonrise
Tue -- 12:51 AM EST     Last Quarter
Tue -- 02:27 AM EST     1.89 feet High Tide
Tue -- 06:52 AM EST     Sunrise
Tue -- 08:25 AM EST     0.78 feet Low Tide
Tue -- 01:01 PM EST     Moonset
Tue -- 02:51 PM EST     2.00 feet High Tide
Tue -- 05:33 PM EST     Sunset
Tue -- 09:05 PM EST     0.71 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Alligator Reef Light, Florida, Tide feet

Long Key
Click for Map
Tue -- 12:10 AM EST     Moonrise
Tue -- 12:51 AM EST     Last Quarter
Tue -- 02:21 AM EST     0.53 knots Max Flood
Tue -- 05:30 AM EST     -0.00 knots Slack
Tue -- 06:53 AM EST     Sunrise
Tue -- 08:28 AM EST     -0.79 knots Max Ebb
Tue -- 11:54 AM EST     0.00 knots Slack
Tue -- 01:02 PM EST     Moonset
Tue -- 03:00 PM EST     0.66 knots Max Flood
Tue -- 05:33 PM EST     Sunset
Tue -- 06:12 PM EST     -0.00 knots Slack
Tue -- 09:09 PM EST     -0.81 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION

Long Key, east of drawbridge, Florida Current, knots

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