National Weather Service Marine Forecast FZUS52 KKEY

FZUS52 KKEY 210242
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
1042 PM EDT Mon Jul 20 2026

Florida Bay, Hawk Channel and Straits of Florida from Ocean Reef to south of Dry Tortugas, and the extreme southeastern Gulf of America, 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.

The Wave Detail section highlights the period and direction of origin for the highest-energy waves, as well as any long-period swells moving in a different direction than the wind.

GMZ005-211445
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 1042 PM EDT Mon Jul 20 2026

SYNOPSIS
As of 8 PM EDT, recently formed Tropical Storm Bertha was centered over the northeastern Gulf waters. Bertha is expected to crawl northwestward during the overnight hours into Tuesday morning, followed by a turn toward the west. On the forecast track, TS Bertha will move near or along the northern Gulf coast during the next several days. Closer to home, an Atlantic ridge of high pressure will extend to the Florida Peninsula for the next several days. Moderate breezes, especially across the SE Gulf will slacken to gentle to moderate this afternoon. Thereafter, breezes will continue to peak overnight and lull during the day through Thursday.

The Approximate Shoreward Edge of the Gulf Stream as of July 17, 2026...

49 NM South of Dry Tortugas Light...on Loggerhead Key. 51 NM South of Cosgrove Shoal Light...off the Marquesas Keys. 38 NM South of Sand Key Light...off Key West. 22 NM South of Looe Key...off Big Pine Key. 13 NM South of Sombrero Key Light...off Marathon. 6 NM Southeast of Alligator Reef Light...off Islamorada. 2 NM Southeast of Molasses Reef Light...off Key Largo. 1 NM Southeast of Carysfort Reef Light...off Ocean Reef.

Gulf Stream Information Courtesy of the National Weather Service in Key West, using data from RTOFS and NASA SPoRT SST.

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GMZ031-211445
Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound
1042 PM EDT Mon Jul 20 2026

OVERNIGHT
Southeast to south winds near 10 knots, becoming southeast and increasing to near 15 knots. Bay waters a light chop, becoming a moderate chop. A slight chance of showers and thunderstorms.

TUESDAY
Southeast winds near 15 knots, decreasing to near 10 knots. Bay waters a moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

TUESDAY NIGHT
East to southeast winds near 10 knots, becoming southeast and increasing to 10 to 15 knots. Bay waters a light chop, becoming a light to moderate chop. A slight chance of showers and thunderstorms.

WEDNESDAY
East to southeast winds 10 to 15 knots, decreasing to near 10 knots. Bay waters a light to moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds near 10 knots. Bay waters a light chop.

THURSDAY
East winds near 10 knots. Bay waters a light chop. A slight chance of showers and thunderstorms.

THURSDAY NIGHT
Northeast to east winds 10 to 15 knots, becoming 5 to 10 knots. Bay waters a light to moderate chop, becoming smooth to a light chop. A chance of showers and thunderstorms.

FRIDAY
East to southeast winds 5 to 10 knots. Bay waters smooth to a light chop. A slight chance of showers and thunderstorms.

FRIDAY NIGHT
Southeast winds 5 to 10 knots. Bay waters smooth to a light chop. A slight chance of showers and thunderstorms.

SATURDAY
Southeast to south winds 5 to 10 knots. Bay waters smooth to a light chop. A slight chance of showers and thunderstorms.

SATURDAY NIGHT
Southeast to south winds 5 to 10 knots. Bay waters smooth to a light chop. A slight chance of showers and thunderstorms.

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GMZ032-035-211445
Bayside and Gulfside from Craig Key to west end of Seven Mile Bridge
Gulf of America from west end of Seven Mile Bridge to Halfmoon Shoal out to 5 Fathoms
1042 PM EDT Mon Jul 20 2026

OVERNIGHT
Southeast to south winds near 10 knots, becoming southeast and increasing to near 15 knots. Seas 1 to 2 feet. Nearshore waters a light chop, becoming a moderate chop. A slight chance of showers and thunderstorms.

TUESDAY
Southeast winds near 15 knots, decreasing to near 10 knots. Seas 1 to 2 feet, except 2 to 3 feet west of the Marquesas Keys. Nearshore waters a moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

TUESDAY NIGHT
East to southeast winds near 10 knots, becoming southeast and increasing to 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light chop, becoming a light to moderate chop. A slight chance of showers and thunderstorms.

WEDNESDAY
Southeast winds 10 to 15 knots, becoming east to southeast and decreasing to near 10 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop.

THURSDAY
East winds near 10 knots. Seas 1 to 2 feet. Nearshore waters a light chop. A slight chance of showers and thunderstorms.

THURSDAY NIGHT
East winds near 10 knots. Seas 1 to 2 feet. Nearshore waters a light chop. A slight chance of showers and thunderstorms.

FRIDAY
East to southeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. A slight chance of showers and thunderstorms.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. A slight chance of showers and thunderstorms.

SATURDAY
Southeast to south winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop.

SATURDAY NIGHT
Southeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. A slight chance of showers and thunderstorms.

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GMZ042>044-211445
Hawk Channel from Ocean Reef to Craig Key out to the reef
Hawk Channel from Craig Key to west end of Seven Mile Bridge out to the reef
Hawk Channel from west end of Seven Mile Bridge to Halfmoon Shoal out to the reef
1042 PM EDT Mon Jul 20 2026

OVERNIGHT
Southeast to south winds near 10 knots, becoming southeast and increasing to near 15 knots. Seas 2 to 3 feet. Nearshore waters a light chop, becoming a moderate chop. A slight chance of showers and thunderstorms.

TUESDAY
Southeast winds near 15 knots, becoming east to southeast and decreasing to near 10 knots. Seas 2 to 3 feet. Nearshore waters a moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

TUESDAY NIGHT
East to southeast winds near 10 knots, becoming southeast and increasing to 10 to 15 knots. Seas around 2 feet. Nearshore waters a light chop, becoming a light to moderate chop. A slight chance of showers and thunderstorms.

WEDNESDAY
Southeast winds 10 to 15 knots, becoming east to southeast and decreasing to near 10 knots. Seas 2 to 3 feet, subsiding to around 2 feet. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds 10 to 15 knots. Seas around 2 feet. Nearshore waters a light to moderate chop.

THURSDAY
East winds near 10 knots. Seas 1 to 2 feet. Nearshore waters a light chop. A slight chance of showers and thunderstorms.

THURSDAY NIGHT
East winds near 10 knots. Seas 1 to 2 feet. Nearshore waters a light chop. A chance of showers and thunderstorms.

FRIDAY
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet. Nearshore waters smooth to a light chop. A slight chance of showers.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop. A slight chance of showers and thunderstorms.

SATURDAY
Southeast winds 5 to 10 knots. Seas around 1 foot. Nearshore waters smooth to a light chop.

SATURDAY NIGHT
Southeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop.

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GMZ052>055-072>075-211445
Straits of Florida from Ocean Reef to Craig Key out 20 NM
Straits of Florida from Craig Key to west end of Seven Mile Bridge out 20 NM
Straits of Florida from west end of Seven Mile Bridge to south of Halfmoon Shoal out 20 NM
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry Tortugas out 20 NM
Straits of Florida from Ocean Reef to Craig Key 20 to 60 NM out
Straits of Florida from Craig Key to west end of Seven Mile Bridge 20 to 60 NM out
Straits of Florida from west end of Seven Mile Bridge to south of Halfmoon Shoal 20 to 60 NM out
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry Tortugas 20 to 60 NM out
1042 PM EDT Mon Jul 20 2026

OVERNIGHT
Southeast to south winds near 10 knots, becoming southeast and increasing to near 15 knots. Seas 2 to 3 feet. Wave Detail: East to southeast 3 feet at 5 seconds and west 1 foot at 5 seconds. A slight chance of showers and thunderstorms.

TUESDAY
Southeast winds 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: East to southeast 3 feet at 5 seconds and west 1 foot at 6 seconds. A slight chance of showers and thunderstorms.

TUESDAY NIGHT
East to southeast winds 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: East to southeast 3 feet at 5 seconds and west to northwest 1 foot at 6 seconds. A slight chance of showers and thunderstorms.

WEDNESDAY
East to southeast winds 10 to 15 knots. Seas 2 to 4 feet, occasionally to 5 feet. A slight chance of showers and thunderstorms.

WEDNESDAY NIGHT
East winds 10 to 15 knots. Seas 2 to 4 feet, occasionally to 5 feet.

THURSDAY
East winds 10 to 15 knots. Seas 2 to 4 feet, occasionally to 5 feet.

THURSDAY NIGHT
East winds 10 to 15 knots. Seas 2 to 3 feet. A chance of showers and thunderstorms.

FRIDAY
East winds 5 to 10 knots. Seas 1 to 2 feet.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.

SATURDAY
Southeast winds 5 to 10 knots. Seas 1 to 2 feet.

SATURDAY NIGHT
East to southeast winds 5 to 10 knots. Seas 1 to 2 feet.

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GMZ033-034-211445
Gulf of America from East Cape Sable to Chokoloskee 20 to 60 NM out and beyond 5 fathoms
Gulf of America including Dry Tortugas and Rebecca Shoal Channel
1042 PM EDT Mon Jul 20 2026

OVERNIGHT
South winds 10 to 15 knots, becoming southeast to south and increasing to near 15 knots. Seas 2 to 3 feet. Wave Detail: South to southwest 3 feet at 4 seconds. A slight chance of showers and thunderstorms.

TUESDAY
Southeast to south winds 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: Southeast 2 feet at 4 seconds and west 2 feet at 6 seconds. A slight chance of showers and thunderstorms.

TUESDAY NIGHT
Southeast winds 5 to 10 knots, increasing to 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: East to southeast 2 feet at 4 seconds and west 2 feet at 6 seconds.

WEDNESDAY
Southeast winds near 10 knots, becoming east to southeast and decreasing to 5 to 10 knots. Seas around 2 feet.

WEDNESDAY NIGHT
East to southeast winds 5 to 10 knots, increasing to near 10 knots. Seas around 2 feet. A slight chance of showers and thunderstorms.

THURSDAY
East winds 5 to 10 knots. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.

THURSDAY NIGHT
East winds 5 to 10 knots. Seas around 2 feet. A slight chance of showers and thunderstorms.

FRIDAY
East winds 5 to 10 knots. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.

FRIDAY NIGHT
East to southeast winds 5 to 10 knots. Seas around 1 foot. A slight chance of showers and thunderstorms.

SATURDAY
Southeast to south winds 5 to 10 knots. Seas around 1 foot.

SATURDAY NIGHT
Southeast winds 5 to 10 knots. Seas around 1 foot. A slight chance of showers and thunderstorms.