FZUS52 KKEY 180832 CCA CWFKEY Coastal Waters Forecast for the Florida Keys National Weather Service Key West FL 421 AM EDT Sat Apr 18 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. GMZ005-182030- Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 421 AM EDT Sat Apr 18 2026 .SYNOPSIS...High pressure over the central North Atlantic will start to loosen its grip across the Keys over the weekend. This will allow for slowly slackening breezes, potentially becoming variable sometime Sunday/Sunday night. A front approaches the Keys sometime Monday/Monday evening with a strong high pressure quickly filling in the wake on Tuesday. Fresh to strong breezes will prevail as early as Monday night, and hazardous marine conditions will continue through at least mid week. The Approximate Shoreward Edge of the Gulf Stream as of April 16... 16 NM South of Dry Tortugas Light...on Loggerhead Key. 12 NM South of Cosgrove Shoal Light...off the Marquesas Keys. 22 NM South of Sand Key Light...off Key West. 30 NM South of Looe Key...off Big Pine Key. 26 NM Southeast of Sombrero Key Light...off Marathon. 20 NM Southeast of Alligator Reef Light...off Islamorada. 15 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. $$ GMZ031-182030- Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound- 421 AM EDT Sat Apr 18 2026 .TODAY...East to southeast winds 10 to 15 knots, decreasing to near 10 knots. Bay waters a light to moderate chop, becoming a light chop. .TONIGHT...East winds near 10 knots, decreasing to 5 to 10 knots. Bay waters a light chop, becoming smooth to a light chop. A slight chance of showers. .SUNDAY...East winds 5 to 10 knots, becoming variable near 5 knots in the afternoon. Bay waters smooth to a light chop, becoming smooth. .SUNDAY NIGHT...North to northeast winds 5 to 10 knots, increasing to near 10 knots. Bay waters smooth to a light chop, becoming a light chop. A slight chance of showers. .MONDAY...Northeast winds 5 to 10 knots, becoming east 10 to 15 knots in the afternoon. Bay waters smooth to a light chop, becoming a light to moderate chop. A slight chance of showers and thunderstorms. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots after midnight. Bay waters choppy, increasing to very rough after midnight. A chance of showers with a slight chance of thunderstorms. .TUESDAY...Northeast winds near 25 knots. Bay waters extremely rough. A slight chance of showers. .TUESDAY NIGHT...Northeast to east winds near 25 knots, decreasing to 20 to 25 knots. Bay waters extremely rough, becoming very rough. .WEDNESDAY...Northeast to east winds near 20 knots. Bay waters rough. .WEDNESDAY NIGHT...Northeast to east winds near 20 knots, decreasing to 15 to 20 knots. Bay waters rough, becoming choppy. $$ GMZ032-035-182030- 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- 421 AM EDT Sat Apr 18 2026 .TODAY...East to southeast winds 10 to 15 knots, decreasing to near 10 knots. Seas 1 to 2 feet, subsiding to around 1 foot. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers early this morning. .TONIGHT...East winds near 10 knots. Seas around 1 foot. Nearshore waters a light chop. A slight chance of showers. .SUNDAY...Northeast winds 5 to 10 knots. Seas 1 foot or less. Nearshore waters smooth to a light chop. .SUNDAY NIGHT...Northwest to north winds 5 to 10 knots, increasing to 10 to 15 knots. Seas 1 foot or less, building to 1 to 2 feet. Nearshore waters smooth to a light chop, becoming a light to moderate chop. A slight chance of showers. .MONDAY...North to northeast winds 10 to 15 knots, becoming northeast to east and briefly decreasing to 5 to 10 knots in the late morning and early afternoon. Seas 1 to 2 feet. Nearshore waters a light to moderate chop, becoming smooth to a light chop. A slight chance of showers. .MONDAY NIGHT...Northeast winds near 15 knots, increasing to 20 to 25 knots after midnight. Seas 1 to 2 feet, building to 2 to 4 feet, occasionally to 5 feet. West of the Marquesas Keys, seas 2 to 3 feet, building to 4 to 5 feet, occasionally to 6 feet. Nearshore waters choppy, becoming very rough. A chance of showers with a slight chance of thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Seas 3 to 5 feet, occasionally to 6 feet, except 5 to 6 feet, occasionally to 8 feet west of the Marquesas Keys. Nearshore waters extremely rough. A slight chance of showers. .TUESDAY NIGHT...Northeast to east winds 20 to 25 knots. Seas 3 to 5 feet, occasionally to 6 feet, except 5 to 6 feet, occasionally to 8 feet west of the Marquesas Keys. Nearshore waters very rough. .WEDNESDAY...East winds near 20 knots. Seas 2 to 4 feet, occasionally to 5 feet, except 4 to 6 feet, occasionally to 8 feet west of the Marquesas Keys. Nearshore waters rough. .WEDNESDAY NIGHT...East winds near 20 knots, decreasing to 15 to 20 knots. Seas 2 to 3 feet, except 4 to 5 feet, occasionally to 6 feet west of the Marquesas Keys. Nearshore waters rough, becoming choppy. $$ GMZ042>044-182030- 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- 421 AM EDT Sat Apr 18 2026 .TODAY...East to southeast winds 10 to 15 knots, decreasing to near 10 knots. Seas around 2 feet, subsiding to 1 to 2 feet. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers early this morning. .TONIGHT...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. A slight chance of showers. .SUNDAY...Northeast to east winds 5 to 10 knots, becoming variable in the afternoon. Seas 1 to 2 feet, subsiding to around 1 foot. Nearshore waters smooth to a light chop. .SUNDAY NIGHT...North to northeast winds 5 to 10 knots, increasing to near 10 knots. Seas around 1 feet, except building to 1 to 2 feet west of Cosgrove Shoal Light. Nearshore waters smooth to a light chop, becoming a light chop. A slight chance of showers. .MONDAY...North to northeast winds 10 to 15 knots, becoming northeast to east and briefly decreasing to near 10 knots in the late morning and early afternoon. Seas around 1 foot, except 1 to 2 feet west of Cosgrove Shoal Light. Nearshore waters a light to moderate chop, becoming a light chop. A slight chance of showers. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots after midnight. Seas 1 to 2 feet, building to 3 to 5 feet, occasionally to 6 feet. Nearshore waters choppy, becoming very rough. A chance of showers with a slight chance of thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Seas 4 to 6 feet, occasionally to 8 feet. Nearshore waters extremely rough. A slight chance of showers. .TUESDAY NIGHT...Northeast to east winds near 25 knots, decreasing to 20 to 25 knots. Seas 4 to 6 feet, occasionally to 8 feet. Nearshore waters extremely rough, becoming very rough. .WEDNESDAY...Northeast to east winds near 20 knots. Seas 4 to 6 feet, occasionally to 8 feet. Nearshore waters rough. .WEDNESDAY NIGHT...East winds near 20 knots, decreasing to 15 to 20 knots. Seas 3 to 5 feet, occasionally to 6 feet. Nearshore waters rough, becoming choppy. A slight chance of showers. $$ GMZ052>055-072>075-182030- 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- 421 AM EDT Sat Apr 18 2026 .TODAY...East to southeast winds 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: East 3 feet at 5 seconds. A slight chance of showers early this morning. .TONIGHT...East winds near 15 knots, decreasing to 10 to 15 knots. Seas 2 to 3 feet. Wave Detail: East 3 feet at 5 seconds. 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. Wave Detail: East 2 feet at 5 seconds. A slight chance of showers. .SUNDAY NIGHT...Northeast winds 5 to 10 knots, increasing to 10 to 15 knots after midnight. Seas 1 to 2 feet. A slight chance of showers. .MONDAY...Northeast winds 10 to 15 knots, briefly decreasing to near 10 knots in the afternoon. Seas 1 to 3 feet. A slight chance of showers. .MONDAY NIGHT...Northeast winds near 15 knots, increasing to 20 to 25 knots after midnight. Seas 2 to 4 feet, occasionally to 5 feet, building to 5 to 7 feet, occasionally to 9 feet. A chance of showers with a slight chance of thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Seas 7 to 10 feet, occasionally to 13 feet, building to 9 to 11 feet, occasionally to 14 feet. A chance of showers with a slight chance of thunderstorms. .TUESDAY NIGHT...Northeast to east winds near 25 knots. Seas 8 to 11 feet, occasionally to 14 feet. A slight chance of showers. .WEDNESDAY...Northeast to east winds 20 to 25 knots, decreasing to near 20 knots. Seas 7 to 10 feet, occasionally to 13 feet, subsiding to 6 to 8 feet, occasionally to 10 feet. A slight chance of showers. .WEDNESDAY NIGHT...East winds near 20 knots. Seas 5 to 8 feet, occasionally to 10 feet. A slight chance of showers and thunderstorms. $$ GMZ033-034-182030- Gulf of America from East Cape Sable to Chokoloskee 20 to 60 NM out and beyond 5 fathoms- Gulf of America including Dry Tortugas and Rebecca Shoal Channel- 421 AM EDT Sat Apr 18 2026 .TODAY...East winds near 10 knots, decreasing to 5 to 10 knots. Seas 1 to 2 feet, subsiding to around 1 foot. Wave Detail: East 1 foot at 3 seconds. A slight chance of showers early this morning. .TONIGHT...East winds 5 to 10 knots. Seas around 1 foot. Wave Detail: East 1 foot at 3 seconds. A slight chance of showers. .SUNDAY...Northeast to east winds 5 to 10 knots, becoming northwest to north near 10 knots late. Seas around 1 foot. Wave Detail: Northwest to north 1 foot at 2 seconds and northeast to east 1 foot at 3 seconds. .SUNDAY NIGHT...Northwest to north winds 10 to 15 knots. Seas 1 to 2 feet, building to around 2 feet. .MONDAY...North to northeast winds 10 to 15 knots, becoming northeast and briefly decreasing to 10 knots in the afternoon. Seas around 2 feet. A slight chance of showers. .MONDAY NIGHT...Northeast winds 15 to 20 knots, increasing to around 25 knots after midnight. Seas 2 to 3 feet, building to 4 to 6 feet, occasionally to 8 feet. A slight chance of showers. .TUESDAY...Northeast to east winds near 25 knots, decreasing to 20 to 25 knots. Seas 5 to 7 feet, occasionally to 9 feet. A slight chance of showers. .TUESDAY NIGHT...Northeast to east winds 20 to 25 knots. Seas 5 to 7 feet, occasionally to 9 feet. .WEDNESDAY...East winds near 20 knots, briefly decreasing to 10 to 15 knots in the afternoon. Seas 5 to 7 feet, occasionally to 9 feet, subsiding to 3 to 5 feet, occasionally to 6 feet. .WEDNESDAY NIGHT...East winds 15 to 20 knots. Seas 4 to 5 feet, occasionally to 6 feet. A slight chance of showers. $$