350
FZUS52 KKEY 180913
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
513 AM EDT Tue Aug 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.

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.

GMZ005-182115-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
513 AM EDT Tue Aug 18 2026

.SYNOPSIS...
An atlantic ridge axis draped across the coastal waters of the
Florida Keys will maintain a mostly variable wind pattern this
week with wind speeds mainly less than 10 knots. However, brief
increases in wind speeds may occur at times in the evening hours
with winds occasionally approaching 15 knots at times, mostly in
the Upper Keys, so exercise cautionary conditions could briefly
occur. In addition, the presence of saharan air across the Florida
Keys will keep near zero rain chances through the middle of the
week with a very small increase in rain chances by the end of the
week as moisture slowly recovers. The best rain chances late in
the week will typically occur north of the Island Chain in the Bay
and Gulf side waters, though any precipitation activity in
general is expected to be isolated to scattered in nature.

The Approximate Shoreward Edge of the Gulf Stream as of August
13, 2026...

38 NM South of Dry Tortugas Light...on Loggerhead Key.
20 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
17 NM South of Sand Key Light...off Key West.
21 NM South of Looe Key...off Big Pine Key.
18 NM Southeast of Sombrero Key Light...off Marathon.
 7 NM Southeast of Alligator Reef Light...off Islamorada.
 7 NM Southeast of Molasses Reef Light...off Key Largo.
 2 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.

$$

GMZ031-182115-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
513 AM EDT Tue Aug 18 2026

.TODAY...Northwest winds near 5 knots, becoming west 5 to 10 knots.
Bay waters smooth, becoming smooth to a light chop.
.TONIGHT...West to northwest winds 10 to 15 knots, becoming
northwest 5 to 10 knots. Bay waters a light to moderate chop,
becoming smooth to a light chop.
.WEDNESDAY...Northwest winds 5 to 10 knots, becoming southwest to
west. Bay waters smooth to a light chop.
.WEDNESDAY NIGHT...West to northwest winds 5 to 10 knots. Bay
waters smooth to a light chop. A slight chance of showers and
thunderstorms.
.THURSDAY...Southwest to west winds 5 to 10 knots. Bay waters
smooth to a light chop. A slight chance of showers and
thunderstorms.
.THURSDAY NIGHT...Southwest winds near 5 knots, becoming
southeast to south. Bay waters smooth. A slight chance of showers
and thunderstorms.
.FRIDAY...South to southwest winds near 5 knots. Bay waters
smooth. A slight chance of showers and thunderstorms.
.FRIDAY NIGHT...Southeast to south winds near 5 knots. Bay waters
smooth. A slight chance of showers.
.SATURDAY...South winds near 5 knots. Bay waters smooth. A slight
chance of showers and thunderstorms.
.SATURDAY NIGHT...Southeast winds near 5 knots. Bay waters
smooth. A slight chance of showers.

$$

GMZ032-035-182115-
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-
513 AM EDT Tue Aug 18 2026

.TODAY...North winds near 5 knots, becoming northwest 5 to 10
knots. Seas 1 foot or less. Nearshore waters smooth, becoming
smooth to a light chop.
.TONIGHT...Northwest winds 10 to 15 knots, becoming 5 to 10 knots.
Seas around 1 foot. Nearshore waters a light to moderate chop,
becoming smooth to a light chop.
.WEDNESDAY...Northwest winds 5 to 10 knots. Seas 1 foot or less.
Nearshore waters smooth to a light chop.
.WEDNESDAY NIGHT...Northwest winds 10 to 15 knots, becoming 5 to
10 knots. Seas around 1 foot. Nearshore waters a light to
moderate chop, becoming smooth to a light chop. A slight chance of
showers and thunderstorms.
.THURSDAY...West winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. A slight chance of showers and
thunderstorms.
.THURSDAY NIGHT...West winds near 5 knots, becoming southeast to
south. Seas 1 foot or less. Nearshore waters smooth. A slight
chance of showers and thunderstorms.
.FRIDAY...South to southwest winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth.
.FRIDAY NIGHT...Southeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. A slight chance of showers.
.SATURDAY...South winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. A slight chance of showers and
thunderstorms.
.SATURDAY NIGHT...Southeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. A slight chance of showers and
thunderstorms.

$$

GMZ042>044-182115-
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-
513 AM EDT Tue Aug 18 2026

.TODAY...North to northeast winds near 5 knots, becoming
northwest 5 to 10 knots. Seas around 1 foot. Nearshore waters
smooth to a light chop.
.TONIGHT...Northwest winds 5 to 10 knots. Seas around 1 foot.
Nearshore waters smooth to a light chop.
.WEDNESDAY...Northwest winds 5 to 10 knots. Seas around 1 foot.
Nearshore waters smooth to a light chop.
.WEDNESDAY NIGHT...Northwest winds 5 to 10 knots. Seas around 1
foot. Nearshore waters smooth to a light chop.
.THURSDAY...West winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. A slight chance of showers and
thunderstorms.
.THURSDAY NIGHT...West winds near 5 knots, becoming southeast to
south after midnight. Seas 1 foot or less. Nearshore waters
smooth, becoming smooth to a light chop.
.FRIDAY...South winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth.
.FRIDAY NIGHT...Southeast winds near 5 knots. Seas around 1 foot.
Nearshore waters smooth.
.SATURDAY...Southeast to south winds near 5 knots. Seas around
1 foot. Nearshore waters smooth. A slight chance of showers.
.SATURDAY NIGHT...East to southeast winds near 5 knots. Seas
around 1 foot. Nearshore waters smooth. A slight chance of
showers.

$$

GMZ052>055-072>075-182115-
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-
513 AM EDT Tue Aug 18 2026

.TODAY...Northeast to east winds near 5 knots, becoming northwest
5 to 10 knots. Seas 1 to 2 feet. Wave Detail: East 1 foot at 4
seconds.
.TONIGHT...Northwest to north winds 5 to 10 knots. Seas around
1 to 2 feet. Wave Detail: East 1 foot at 3 seconds.
.WEDNESDAY...Northwest to north winds near 5 knots. Seas around 1
foot.
.WEDNESDAY NIGHT...Northwest winds 5 to 10 knots. Seas 1 to 2 feet.
.THURSDAY...South to southwest winds near 5 knots, becoming west
to northwest around 5 knots. Seas around 1 foot.
.THURSDAY NIGHT...Northeast winds 5 to 10 knots, becoming
southeast. Seas 1 to 2 feet.
.FRIDAY...East to southeast winds near 5 knots. Seas around 1
foot.
.FRIDAY NIGHT...East to southeast winds 5 to 10 knots. Seas 1 to 2
feet. A slight chance of showers.
.SATURDAY...East to southeast winds near 5 knots. Seas around
1 foot.
.SATURDAY NIGHT...East to southeast winds 5 to 10 knots. Seas 1 to
2 feet. A slight chance of showers and thunderstorms.

$$

GMZ033-034-182115-
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-
513 AM EDT Tue Aug 18 2026

.TODAY...North winds 5 to 10 knots. Seas around 1 foot. Wave
Detail: Northwest to north 1 foot at 3 seconds.
.TONIGHT...Northwest winds 5 to 10 knots. Seas around 1 foot.
Wave Detail: Northwest to north 1 foot at 3 seconds.
.WEDNESDAY...Northwest winds 5 to 10 knots. Seas 1 to 2 feet.
Wave Detail: Northwest 2 feet at 5 seconds.
.WEDNESDAY NIGHT...Northwest winds 5 to 10 knots. Seas 1 to
2 feet. A slight chance of showers and thunderstorms.
.THURSDAY...Northwest winds 5 to 10 knots. Seas around 1 foot. A
slight chance of showers and thunderstorms.
.THURSDAY NIGHT...West to northwest winds 5 to 10 knots, becoming
south. Seas around 1 foot. A slight chance of showers and
thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots. Seas around
1 foot.
.FRIDAY NIGHT...Northeast winds near 5 knots, becoming southeast
to south. Seas around 1 foot. A slight chance of showers and
thunderstorms.
.SATURDAY...Southwest winds near 5 knots. Seas around 1 foot. A
slight chance of showers.
.SATURDAY NIGHT...North winds near 5 knots, becoming southeast to
south. Seas around 1 foot. A slight chance of showers.

$$