FZUS52 KKEY 160820 CWFKEY Coastal Waters Forecast for the Florida Keys National Weather Service Key West FL 420 AM EDT Thu Apr 16 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. Wave Detail will include details about the period and direction of origin for the highest energy waves. Long-period swells coming from a different direction than the wind would be included in the Wave Detail. GMZ005-162030- Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 420 AM EDT Thu Apr 16 2026 .SYNOPSIS...High pressure over the central North Atlantic will maintain gentle to moderate northeast to east breezes through the next several forecast periods. Breezes likely will lull from late morning into the late afternoon across the Gulf/Bayside waters due to the heating of South Florida. As the high moves farther eastward and slowly weakens, easterly breezes will slacken Thursday through Sunday. A back door front will slide through sometime Sunday with a strong high pressure quickly filling in the wake. This will allow for breezes to freshen with a period of fresh to occasionally strong breezes possible early next week. The Approximate Shoreward Edge of the Gulf Stream as of April 10... 16 NM South of Dry Tortugas Light...on Loggerhead Key. 21 NM South of Cosgrove Shoal Light...off the Marquesas Keys. 23 NM South of Sand Key Light...off Key West. 37 NM South of Looe Key...off Big Pine Key. 29 NM Southeast of Sombrero Key Light...off Marathon. 18 NM Southeast of Alligator Reef Light...off Islamorada. 13 NM Southeast of Molasses Reef Light...off Key Largo. 9 NM Southeast of Carysfort Reef Light...off Ocean Reef. Gulf Stream Information Courtesy of the National Weather Service in Key West based on products from NASA SPoRT and RTOFS. $$ GMZ031-162030- Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound- 420 AM EDT Thu Apr 16 2026 .TODAY...Northeast to east winds 10 to 15 knots. Bay waters a light to moderate chop. .TONIGHT...Northeast to east winds near 15 knots, decreasing to 10 to 15 knots. Bay waters a moderate chop, becoming a light to moderate chop. .FRIDAY...Northeast to east winds 10 to 15 knots. Bay waters a light to moderate chop. .FRIDAY NIGHT...Northeast to east winds 10 to 15 knots. Bay waters a light to moderate chop. A slight chance of showers. .SATURDAY...East winds 10 to 15 knots. Bay waters a light to moderate chop. .SATURDAY NIGHT...East winds 10 to 15 knots, decreasing to near 10 knots. Bay waters a light to moderate chop, becoming a light chop. A slight chance of showers. .SUNDAY...East to southeast winds 5 to 10 knots, becoming variable. Bay waters smooth to a light chop. .SUNDAY NIGHT...North to northeast winds increasing to near 10 knots. Bay waters becoming a light chop. .MONDAY...Northeast to east winds increasing to 10 to 15 knots. Bay waters becoming a light to moderate chop. A slight chance of showers. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots. Bay waters choppy, becoming very rough. A slight chance of showers. $$ GMZ032-035-162030- 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- 420 AM EDT Thu Apr 16 2026 .TODAY...Northeast to east winds 10 to 15 knots. Seas 1 to 2 feet, subsiding to around 1 foot. West of the Marquesas Keys, seas 2 to 3 feet, subsiding to 1 to 2 feet. Nearshore waters a light to moderate chop. .TONIGHT...Northeast to east winds 10 to 15 knots. Seas around 1 foot, except 1 to 2 feet west of the Marquesas Keys. Nearshore waters a light to moderate chop. .FRIDAY...Northeast to east winds 10 to 15 knots, briefly decreasing to near 10 knots in the afternoon. Seas around 1 foot, except 1 to 2 feet west of the Marquesas Keys. Nearshore waters a light to moderate chop, becoming a light chop. .FRIDAY NIGHT...East winds 10 to 15 knots. Seas around 1 foot, except 1 to 2 feet west of the Marquesas Keys. Nearshore waters a light to moderate chop. A slight chance of showers. .SATURDAY...East winds 10 to 15 knots, briefly decreasing to near 10 knots in the afternoon. Seas around 1 foot, except 1 to 2 feet west of the Marquesas Keys. Nearshore waters a light to moderate chop, becoming a light chop. .SATURDAY NIGHT...East winds 10 to 15 knots, decreasing to near 10 knots late. Seas around 1 foot, except 1 to 2 feet west of the Marquesas Keys. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers. .SUNDAY...Northeast to east winds 5 to 10 knots, becoming northwest to north in the afternoon. Seas subsiding to 1 foot or less. Nearshore waters smooth to a light chop. .SUNDAY NIGHT...North winds increasing to near 10 knots. Seas building to 1 to 2 feet. Nearshore waters becoming a light chop. .MONDAY...Northeast winds near 10 knots, increasing to near 15 knots. Seas 1 to 2 feet, except building to 2 to 3 feet west of the Marquesas Keys. Nearshore waters a light chop, becoming a moderate chop. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots. Seas building to 2 to 4 feet, occasionally to 5 feet, except building to 3 to 5 feet, occasionally to 6 feet west of the Marquesas Keys. Nearshore waters choppy, becoming very rough. A slight chance of showers. $$ GMZ042>044-162030- 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- 420 AM EDT Thu Apr 16 2026 .TODAY...Northeast to east winds 10 to 15 knots. Seas 2 to 3 feet. Nearshore waters a light to moderate chop. .TONIGHT...Northeast to east winds near 15 knots, decreasing to 10 to 15 knots. Seas 2 to 3 feet. Nearshore waters a moderate chop, becoming a light to moderate chop. .FRIDAY...Northeast to east winds 10 to 15 knots. Seas around 2 feet, subsiding to 1 to 2 feet. Nearshore waters a light to moderate chop. .FRIDAY NIGHT...Northeast to east winds near 15 knots, decreasing to 10 to 15 knots. Seas around 2 feet. Nearshore waters a moderate chop, becoming a light to moderate chop. A slight chance of showers. .SATURDAY...East winds 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop. .SATURDAY NIGHT...East winds 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop. A slight chance of showers. .SUNDAY...Northeast to east winds near 10 knots, becoming north to northeast 5 to 10 knots. Seas 1 to 2 feet, subsiding to around 1 foot. Nearshore waters a light chop, becoming smooth to a light chop. .SUNDAY NIGHT...North to northeast winds increasing to near 10 knots. Seas around 1 foot, except 1 to 2 feet west of Cosgrove Shoal Light. Nearshore waters becoming a light chop. .MONDAY...Northeast winds near 10 knots, increasing to 10 to 15 knots. Seas building to 1 to 2 feet, except building to 2 to 3 feet west of Cosgrove Shoal Light. Nearshore waters a light chop, becoming a light to moderate chop. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to northeast to east 20 to 25 knots. Seas building to 2 to 4 feet, occasionally to 5 feet, except building to 4 to 5 feet, occasionally to 6 feet west of Cosgrove Shoal Light. Nearshore waters choppy, becoming very rough. A slight chance of showers. $$ GMZ052>055-072>075-162030- 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- 420 AM EDT Thu Apr 16 2026 .TODAY...Northeast to east winds near 15 knots, decreasing to 10 to 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at 6 seconds. .TONIGHT...Northeast to east winds near 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: Northeast to east 4 feet at 5 seconds. A slight chance of showers. .FRIDAY...Northeast to east winds 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: Northeast to east 3 feet at 5 seconds. A slight chance of showers. .FRIDAY NIGHT...Northeast to east winds near 15 knots. Seas 2 to 4 feet, occasionally to 5 feet. A slight chance of showers. .SATURDAY...East winds 10 to 15 knots. Seas 2 to 3 feet. A slight chance of showers. .SATURDAY NIGHT...East winds near 15 knots, decreasing to 10 to 15 knots. Seas 2 to 3 feet. A slight chance of showers. .SUNDAY...Northeast to east winds near 10 knots, decreasing to 5 to 10 knots. Seas 2 to 3 feet, subsiding to 1 to 2 feet. A slight chance of showers. .SUNDAY NIGHT...Northeast winds 5 to 10 knots, increasing to 10 to 15 knots. Seas 1 to 2 feet. .MONDAY...Northeast winds 10 to 15 knots, increasing to near 15 knots. Seas building to 2 to 3 feet. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to northeast to east 20 to 25 knots. Seas 3 to 4 feet, occasionally to 5 feet, building to 5 to 8 feet, occasionally to 10 feet. A slight chance of showers and thunderstorms. $$ GMZ033-034-162030- Gulf of America from East Cape Sable to Chokoloskee 20 to 60 NM out and beyond 5 fathoms- Gulf of America including Dry Tortugas and Rebecca Shoal Channel- 420 AM EDT Thu Apr 16 2026 .TODAY...Northeast to east winds 10 to 15 knots, becoming north to northeast 5 to 10 knots. Seas 2 to 3 feet, subsiding to 1 to 2 feet. Wave Detail: East 2 feet at 4 seconds. .TONIGHT...Northeast winds 5 to 10 knots, becoming northeast to east 10 to 15 knots. Seas 1 to 2 feet. Wave Detail: Northeast to east 2 feet at 3 seconds. .FRIDAY...Northeast winds 10 to 15 knots early, decreasing to 5 to 10 knots. Seas 1 to 2 feet. Wave Detail: Northeast 2 feet at 3 seconds. .FRIDAY NIGHT...Northeast winds 5 to 10 knots, becoming east 10 to 15 knots. Seas 1 to 2 feet. .SATURDAY...East winds 10 to 15 knots, decreasing to 5 to 10 knots. Seas 1 to 2 feet. .SATURDAY NIGHT...Northeast to east winds 5 to 10 knots. Seas subsiding to around 1 foot. A slight chance of showers. .SUNDAY...Northeast to east winds 5 to 10 knots, becoming northwest to north near 10 knots. Seas around 1 foot, building to 1 to 2 feet. .SUNDAY NIGHT...North winds near 10 knots. Seas around 2 feet. .MONDAY...Northeast winds near 10 knots, increasing to 10 to 15 knots. Seas 2 to 3 feet, building to 3 to 4 feet, occasionally to 5 feet. .MONDAY NIGHT...Northeast winds 15 to 20 knots, becoming northeast to east 20 to 25 knots. Seas 3 to 5 feet, occasionally to 6 feet, building to 5 to 7 feet, occasionally to 9 feet. A slight chance of showers. $$ LIW