FZUS52 KKEY 201438 CWFKEY Coastal Waters Forecast for the Florida Keys National Weather Service Key West FL 1038 AM EDT Mon Apr 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. 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. GMZ005-210245- Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas 1038 AM EDT Mon Apr 20 2026 .SYNOPSIS...Breezes will briefly be light to gentle as the Mainland heats up, but will increase towards the late afternoon due to an approaching front. The front is poised to sweep through the Keys this evening followed by a strong high pressure overnight. Moderate to fresh breezes will develop in the early evening and further freshen to fresh to strong breezes after midnight. Hazardous marine conditions are expected to continue through at Wednesday. 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. $$ GMZ031-210245- Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood Sound- 1038 AM EDT Mon Apr 20 2026 ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED LATE TONIGHT... .THIS AFTERNOON...North to northeast winds 5 to 10 knots, becoming northeast to east 10 to 15 knots late in the afternoon. Bay waters smooth to a light chop, becoming a light to moderate chop. A chance of showers with a slight chance of thunderstorms. Bay waters rough and winds higher in and around thunderstorms. .TONIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots. Bay waters choppy, becoming very rough. A chance of showers with a slight chance of thunderstorms. Bay waters rough and winds higher in and around thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Bay waters extremely rough. .TUESDAY NIGHT...Northeast to east winds near 25 knots, decreasing to 20 to 25 knots. Bay waters extremely rough, becoming very rough. .WEDNESDAY...East winds near 20 knots, decreasing to 15 to 20 knots. Bay waters rough, becoming choppy. .WEDNESDAY NIGHT...East winds 15 to 20 knots, decreasing to near 15 knots. Bay waters choppy, becoming a moderate chop. A slight chance of showers. .THURSDAY...East winds near 15 knots. Bay waters a moderate chop. A slight chance of showers. .THURSDAY NIGHT...East winds near 15 knots. Bay waters a moderate chop. A slight chance of showers and thunderstorms. .FRIDAY...East to southeast winds 10 to 15 knots. Bay waters a light to moderate chop. A slight chance of showers and thunderstorms. .FRIDAY NIGHT...East winds 10 to 15 knots. Bay waters a light to moderate chop. A slight chance of showers. $$ GMZ032-035-210245- 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- 1038 AM EDT Mon Apr 20 2026 ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED LATE TONIGHT... .THIS AFTERNOON...North to northeast winds 5 to 10 knots, becoming northeast 10 to 15 knots late in the afternoon. Seas 1 to 2 feet. Nearshore waters smooth to a light chop, becoming a light to moderate chop. A chance of showers with a slight chance of thunderstorms. Winds and seas higher in and around thunderstorms. .TONIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots after midnight. Seas 1 to 3 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. Winds and seas higher in and around 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 near 25 knots, decreasing to 20 to 25 knots. Seas 3 to 5 feet, occasionally to 6 feet, subsiding to 2 to 4 feet, occasionally to 5 feet. West of the Marquesas Keys, seas 5 to 6 feet, occasionally to 8 feet. Nearshore waters extremely rough, becoming very rough. .WEDNESDAY...East winds near 20 knots, decreasing to 15 to 20 knots. Seas 2 to 4 feet, occasionally to 5 feet, except 4 to 5 feet, occasionally to 6 feet west of the Marquesas Keys. Nearshore waters rough, becoming choppy. .WEDNESDAY NIGHT...East winds 15 to 20 knots. Seas 2 to 3 feet, except 3 to 4 feet, occasionally to 5 feet west of the Marquesas Keys. Nearshore waters choppy. A slight chance of showers. .THURSDAY...East winds near 15 knots. Seas 1 to 3 feet, except 3 to 4 feet, occasionally to 5 feet west of the Marquesas Keys. Nearshore waters a moderate chop. A slight chance of showers. .THURSDAY NIGHT...East winds 15 to 20 knots, decreasing to near 15 knots. Seas 1 to 3 feet, except 3 to 4 feet, occasionally to 5 feet west of the Marquesas Keys. Nearshore waters choppy, becoming a moderate chop. A slight chance of showers and thunderstorms. .FRIDAY...East to southeast winds decreasing to 10 to 15 knots. Seas 1 to 2 feet, except 2 to 3 feet west of the Marquesas Keys. Nearshore waters becoming a light to moderate chop. A slight chance of showers. .FRIDAY NIGHT...East winds 10 to 15 knots. Seas 1 to 2 feet. Nearshore waters a light to moderate chop. A slight chance of showers. $$ GMZ042>044-210245- 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- 1038 AM EDT Mon Apr 20 2026 ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED LATE TONIGHT... .THIS AFTERNOON...North to northeast winds 5 to 10 knots, becoming northeast 10 to 15 knots late in the afternoon. Seas 1 to 2 feet, except building to 2 to 3 feet west of Cosgrove Shoal Light. Nearshore waters smooth to a light chop, becoming a light to moderate chop. A chance of showers with a slight chance of thunderstorms. Winds and seas higher in and around thunderstorms. .TONIGHT...Northeast winds 15 to 20 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 Cosgrove Shoal Light, 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. Winds and seas higher in and around thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Seas 4 to 6 feet, occasionally to 8 feet, except 5 to 7 feet, occasionally to 9 feet west of Cosgrove Shoal Light. 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...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. .WEDNESDAY NIGHT...East winds 15 to 20 knots. Seas 3 to 4 feet, occasionally to 5 feet. Nearshore waters choppy. A slight chance of showers. .THURSDAY...East winds 15 to 20 knots. Seas 2 to 4 feet, occasionally to 5 feet. Nearshore waters choppy. A slight chance of showers. .THURSDAY NIGHT...East winds 15 to 20 knots. Seas 2 to 4 feet, occasionally to 5 feet. Nearshore waters choppy. A slight chance of showers and thunderstorms. .FRIDAY...East to southeast 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. A slight chance of showers. .FRIDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet. Nearshore waters a light to moderate chop. A slight chance of showers. $$ GMZ052>055-072>075-210245- 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- 1038 AM EDT Mon Apr 20 2026 ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED LATE TONIGHT... .THIS AFTERNOON...North to northeast winds 5 to 10 knots, then becoming northeast 10 to 15 knots late in the afternoon. Seas 1 to 2 feet, building to 2 to 3 feet. Wave Detail: Northeast 2 feet at 4 seconds. A slight chance of showers this afternoon. .TONIGHT...Northeast winds 15 to 20 knots, increasing to northeast to east 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. Wave Detail: North 4 feet at 6 seconds, becoming north to northeast 6 feet at 6 seconds. A chance of showers with a slight chance of thunderstorms. Winds and seas higher in and around thunderstorms. .TUESDAY...Northeast to east winds near 25 knots. Seas 7 to 10 feet, occasionally to 13 feet. Wave Detail: Northeast to east 10 feet at 8 seconds and northwest 2 feet at 7 seconds. A chance of showers. .TUESDAY NIGHT...Northeast to east winds near 25 knots, decreasing to 20 to 25 knots. Seas 7 to 10 feet, occasionally to 13 feet. .WEDNESDAY...East winds near 20 to 25 knots early, decreasing to near 20 knots. Seas 6 to 9 feet, occasionally to 11 feet, subsiding to 5 to 7 feet, occasionally to 9 feet. .WEDNESDAY NIGHT...East winds near 20 knots, decreasing to 15 to 20 knots. Seas 5 to 7 feet, occasionally to 9 feet. A slight chance of showers. .THURSDAY...East winds 15 to 20 knots. Seas 4 to 6 feet, occasionally to 8 feet. A chance of showers. .THURSDAY NIGHT...East winds 15 to 20 knots. Seas 4 to 6 feet, occasionally to 8 feet. A chance of showers and thunderstorms. .FRIDAY...East to southeast winds near 15 knots, decreasing to 10 to 15 knots. Seas 4 to 5 feet, occasionally to 6 feet, subsiding to 3 to 4 feet, occasionally to 5 feet. A slight chance of showers and thunderstorms. .FRIDAY NIGHT...East winds 10 to 15 knots. Seas 3 to 4 feet, occasionally to 5 feet. A slight chance of showers and thunderstorms. $$ GMZ033-034-210245- Gulf of America from East Cape Sable to Chokoloskee 20 to 60 NM out and beyond 5 fathoms- Gulf of America including Dry Tortugas and Rebecca Shoal Channel- 1038 AM EDT Mon Apr 20 2026 ...SMALL CRAFT ADVISORY LIKELY WILL BE REQUIRED LATE TONIGHT... .THIS AFTERNOON...North to northeast winds 10 to 15 knots. Seas around 2 feet, building to 2 to 4 feet, occasionally to 5 feet. Wave Detail: Northwest to north 4 feet at 8 seconds and northwest to north 2 feet at 4 seconds. A slight chance of showers this afternoon. .TONIGHT...Northeast winds 15 to 20 knots, increasing to 20 to 25 knots after midnight. Seas 3 to 4 feet, occasionally to 5 feet, building to 4 to 6 feet, occasionally to 8 feet. Wave Detail: North 4 feet at 6 seconds. A slight chance of showers and thunderstorms. Winds and seas higher in and around thunderstorms. .TUESDAY...Northeast to east winds near 25 knots early, decreasing to 20 to 25 knots. Seas 5 to 7 feet, occasionally to 9 feet. Wave Detail: North to northeast 6 feet at 6 seconds. .TUESDAY NIGHT...Northeast to east winds 20 to 25 knots. Seas 4 to 7 feet, occasionally to 9 feet. .WEDNESDAY...East winds near 20 knots, decreasing to 15 to 20 knots. Seas 4 to 6 feet, occasionally to 8 feet, subsiding to 3 to 4 feet, occasionally to 5 feet. .WEDNESDAY NIGHT...East winds 15 to 20 knots. Seas 3 to 4 feet, occasionally to 5 feet. A slight chance of showers. .THURSDAY...East winds near 15 knots. Seas 2 to 4 feet, occasionally to 5 feet. A slight chance of showers. .THURSDAY NIGHT...East to southeast winds 15 to 20 knots, decreasing to near 15 knots. Seas 2 to 4 feet, occasionally to 5 feet. A slight chance of showers and thunderstorms. .FRIDAY...East to southeast winds 10 to 15 knots, decreasing to near 10 knots. Seas 2 to 3 feet. A slight chance of showers. .FRIDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet. $$