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GMZ035 Expires:202310040230;;442303 Fzus52 Kkey 032018 Cwfkey
coastal waters forecast for the florida keys national weather service key west fl 418 pm edt Tue oct 3 2023
florida bay, hawk channel and straits of florida from ocean reef to south of dry tortugas, and the extreme southeastern gulf of mexico, including the florida keys national marine sanctuary
seas are given as significant wave height, which is the average height of the highest 1/3 of the waves. Individual waves may be more than twice the significant wave height.
gmz032-035-040230- bayside and gulf side from craig key to west end of seven mile bridge- gulf of mexico from west end of seven mile bridge to halfmoon shoal out to 5 fathoms- 418 pm edt Tue oct 3 2023
.small craft advisory in effect...
Tonight..Northeast winds near 20 knots, decreasing to near 15 knots. Seas 2 to 3 feet, except around 4 feet west of the marquesas keys. NEarshore waters rough, becoming a moderate chop. Isolated showers.
Wednesday..Northeast to east winds 10 to 15 knots. Seas 2 to 3 feet, subsiding to 1 to 2 feet. West of the marquesas keys seas 3 to 4 feet, subsiding to 2 to 3 feet. NEarshore waters a light to moderate chop. Isolated showers.
Wednesday night..Northeast to east winds near 15 knots, decreasing to 10 to 15 knots. Seas 1 to 2 feet, except 2 to 3 feet west of the marquesas keys. NEarshore waters a moderate chop, becoming a light to moderate chop. Isolated showers.
Thursday..Northeast to east winds 10 to 15 knots, decreasing to near 10 knots. Seas 1 to 2 feet. NEarshore waters a light to moderate chop, becoming a light chop. Isolated showers.
Thursday night..Northeast to east winds near 10 knots. Seas around 1 foot. NEarshore waters a light chop. Isolated showers.
Friday..Northeast winds 5 to 10 knots, becoming north. Seas subsiding to 1 foot or less. NEarshore waters smooth to a light chop. Isolated showers.
Friday night..North winds 5 to 10 knots. Seas 1 foot or less. NEarshore waters smooth to a light chop. Isolated showers.
Saturday..Northwest to north winds 5 to 10 knots. Seas 1 foot or less. NEarshore waters smooth to a light chop. Isolated showers.
Saturday night..Northwest to north winds increasing to 5 to 10 knots. Seas around 1 foot. NEarshore waters becoming smooth to a light chop. Isolated showers and Thunderstorms.
Sunday..Northwest to north winds 5 to 10 knots. Seas 1 to 2 feet, except building to 2 to 3 feet west of the marquesas keys due to a northwest swell. NEarshore waters smooth to a light chop. Isolated showers and Thunderstorms.
Sunday night..Northwest to north winds near 10 knots. Seas 2 to 3 feet, except around 3 feet west of the marquesas keys, due to a northwest swell. NEarshore waters a light chop. Isolated showers and Thunderstorms.

GMZ005 Synopsis For Keys Coastal Waters From Ocean Reef To Dry Tortugas 418 Pm Edt Tue Oct 3 2023
Synopsis..High pressure over the eastern united states will maintain fresh to strong breezes across the coastal waters of the florida keys through this evening. Breezes will then start to diminish through Thursday as the high shifts east into the western north atlantic. Breezes will shift to the northwest later in the week as lower pressure slides north through the western north atlantic.
the approximate shoreward edge of the gulf stream as of september 28...
29 nm south of dry tortugas light...on loggerhead key. 7 nm south of cosgrove shoal light...off the marquesas keys. 6 nm south of sand key light...off key west. 7 nm south of looe key...off big pine key. 7 nm south of sombrero key light...off marathon.
gulf stream information courtesy of the naval oceanographic office.

FXUS62 KKEY 031912 AFDKEY

Area Forecast Discussion National Weather Service Key West FL 312 PM EDT Tue Oct 3 2023

New DISCUSSION, MARINE, AVIATION

DISCUSSION
Issued at 312 PM EDT Tue Oct 3 2023

CIMSS MIMIC TPW highlights a tight moisture gradient bisecting the forecast area, with higher moisture across the Straits of Florida and drier air to the north. This aligns with the surface front draped across the southern half of our forecast area. KBYX is detecting scattered showers and a few brief isolated thunderstorms across the Straits. At the surface, an expansive area of high pressure centered over the Appalachians has maintained a tightened gradient across our forecast area and marine observation platforms along the Reef are recording northeast to east winds generally near 20 knots. Dew points have dropped a few degrees since this morning as the drier airmass continues to filter in, making for a more comfortable afternoon than we have experienced in a while.

A very benign week of weather is on tap for the Florida Keys. The main driver of our sensible weather for the next few forecast periods will be the aforementioned high pressure over the eastern United States. This feature will continue to pump in the modified continental air and keep rain chances well below normal. There may be a few slugs of moisture that move through our area, but the confidence in the timing of any moisture is low, so have maintained 10% PoPs through Saturday. Models appear to favor Thursday night for showers moving off the mainland in northeasterly flow, however, this is highly dependent on if there is enough moisture for development of said storms. The moisture gradient will remain across the Straits for a few days, so have decided to keep thunder that in that area before the front fully washes out. Have kept mention of thunder out of the rest of the forecast area due to the deep dry air aloft that will prevent vertical development of storms through the week.

The area of high pressure will gradually slide eastward into the western North Atlantic, which will allow the gradient to relax further across our area through Thursday. Tropical Storm Phillipe will continue to push northward over the week, which will aid in shoving the high even farther east. TS Phillipe will disrupt the pressure field across the region, and we will be in an area of weak flow by the latter half of the week. Global models are hinting at another frontal boundary late this weekend into early next weekend, however, there is a lot of discrepancies between them in terms of strength and timing. The GFS has it earlier and stronger, which brings moisture across the Keys beginning Saturday night and the ECMWF has it later, which keeps a drier airmass in place longer. Decided to keep 20% rain chances and slight thunder chances in the forecast beginning Saturday night until the forecast becomes more clear as we get closer to the event.

MARINE
Issued at 312 PM EDT Tue Oct 3 2023

A Small Craft Advisory remains in effect for all Florida Keys coastal waters. Also, a Coastal Flood Advisory is in effect for all of the Florida Keys. Boaters can expect less clearance under fixed bridges, especially during the times of high tide. From synopsis, High pressure over the eastern United States will maintain fresh to strong breezes across the coastal waters of the Florida Keys through midnight this evening. Breezes will then start to diminish through Thursday as the high shifts east into the western North Atlantic. Breezes will shift to the northwest later in the week as lower pressure slides north through the western North Atlantic.

AVIATION
(18Z TAFS)
Issued at 312 PM EDT Tue Oct 3 2023

VFR and gusty northeast breezes will prevail at the EYW and MTH terminals through the late afternoon and evening. The stalled frontal boundary over the Straits of Florida will be a focus for showers and storms through Wednesday morning. There will be a brief window between 09 and 15Z when the northern extent of this boundary will push slightly northward towards the Reef and the island chain.
Confidence in shower impacts at the terminals remains low at this time.

CLIMATE
On this day in 2000, the daily record rainfall was recorded at both Key West (3.52") and Marathon (3.10"). Rainfall records date back to 1871 in Key West and 1950 in Marathon.

PRELIMINARY POINT TEMPS/POPS
Key West 79 89 80 89 / 10 10 10 10 Marathon 80 90 80 90 / 10 10 10 10

KEY WATCHES/WARNINGS/ADVISORIES
FL...Coastal Flood Advisory for FLZ076.

GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.

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Key Lois
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Tue -- 06:33 AM EDT     0.09 feet Low Tide
Tue -- 07:18 AM EDT     Sunrise
Tue -- 11:38 AM EDT     Moonset
Tue -- 12:41 PM EDT     1.64 feet High Tide
Tue -- 05:47 PM EDT     0.67 feet Low Tide
Tue -- 07:10 PM EDT     Sunset
Tue -- 10:23 PM EDT     Moonrise
Tue -- 11:50 PM EDT     2.52 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Key Lois, southeast end, Florida, Tide feet

Bahía Honda Harbor (Bridge) Florida Current
Click for Map
Tue -- 01:31 AM EDT     -0.00 knots Slack
Tue -- 05:15 AM EDT     -2.57 knots Max Ebb
Tue -- 07:17 AM EDT     Sunrise
Tue -- 08:49 AM EDT     0.00 knots Slack
Tue -- 11:29 AM EDT     1.76 knots Max Flood
Tue -- 11:38 AM EDT     Moonset
Tue -- 02:58 PM EDT     -0.00 knots Slack
Tue -- 06:02 PM EDT     -1.76 knots Max Ebb
Tue -- 07:10 PM EDT     Sunset
Tue -- 09:24 PM EDT     0.00 knots Slack
Tue -- 10:22 PM EDT     Moonrise
Tue -- 11:27 PM EDT     0.94 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION

Bahia Honda Harbor (Bridge) Florida Current, knots

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Key West, FL,