635
FZUS52 KKEY 180831
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
431 AM EDT Mon Aug 18 2025

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.

GMZ005-182045-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
431 AM EDT Mon Aug 18 2025

.SYNOPSIS...A broad ridge stretching from the North Atlantic
westward across the Florida Peninsula will result in light to
gentle easterly breezes across the Keys coastal waters through
early this week. As Hurricane Erin approaches and passes by The
Bahamas and away from the Keys, breezes will veer to the north and
freshen before gradually backing to the south by the end of the
week.

The Approximate Shoreward Edge of the Gulf Stream as of
August 14...

45 NM South of Dry Tortugas Light...on Loggerhead Key.
34 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
41 NM South of Sand Key Light...off Key West.
24 NM South of Looe Key...off Big Pine Key.
18 NM Southeast of Sombrero Key Light...off Marathon.
 9 NM Southeast of Alligator Reef Light...off Islamorada.
 5 NM Southeast of Molasses Reef Light...off Key Largo.
 3 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.

$$

GMZ031-182045-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
431 AM EDT Mon Aug 18 2025

.TODAY...East winds near 5 knots, becoming northwest. Bay waters
smooth. Scattered showers and isolated thunderstorms.
.TONIGHT...Northwest to north winds 5 to 10 knots. Bay waters
smooth to a light chop. Scattered showers and isolated
thunderstorms.
.TUESDAY...Northwest winds 5 to 10 knots. Bay waters smooth to a
light chop. Scattered showers and isolated thunderstorms.
.TUESDAY NIGHT...Northwest winds near 10 knots, decreasing to 5
to 10 knots. Bay waters a light chop, becoming smooth to a light
chop. Scattered showers and isolated thunderstorms.
.WEDNESDAY...West winds near 10 knots. Bay waters a light chop.
Scattered showers and isolated thunderstorms.
.WEDNESDAY NIGHT...West winds near 10 knots. Bay waters a light
chop. Scattered showers and isolated thunderstorms.
.THURSDAY...Southwest to west winds near 10 knots. Bay waters a
light chop. Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds 5 to 10 knots. Bay
waters smooth to a light chop. Scattered showers and isolated
thunderstorms.
.FRIDAY...Southwest winds near 5 knots. Bay waters smooth.
Scattered showers and isolated thunderstorms.
.FRIDAY NIGHT...South winds near 5 knots, becoming east to
southeast. Bay waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ032-035-182045-
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-
431 AM EDT Mon Aug 18 2025

.TODAY...East to southeast winds near 5 knots, becoming northwest.
Seas 1 foot or less. Nearshore waters smooth. Scattered showers
and isolated thunderstorms.
.TONIGHT...Northwest to north winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Scattered showers
and isolated thunderstorms.
.TUESDAY...Northwest winds 5 to 10 knots, increasing to near 10
knots. Seas 1 foot or less, building to around 1 foot. Nearshore
waters smooth to a light chop, becoming a light chop. Scattered
showers and isolated thunderstorms.
.TUESDAY NIGHT...Northwest winds near 10 knots. Seas around 1
foot. Nearshore waters a light chop. Scattered showers and
isolated thunderstorms.
.WEDNESDAY...West to northwest winds near 10 knots. Seas around 1
foot. Nearshore waters a light chop. Scattered showers and
isolated thunderstorms.
.WEDNESDAY NIGHT...West winds near 10 knots. Seas around 1 foot.
Nearshore waters a light chop. Scattered showers and isolated
thunderstorms.
.THURSDAY...Southwest to west winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Scattered showers
and isolated thunderstorms.
.THURSDAY NIGHT...Southwest winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.FRIDAY...South to southwest winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.FRIDAY NIGHT...Southeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ042>044-182045-
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-
431 AM EDT Mon Aug 18 2025

.TODAY...East to southeast winds near 5 knots, becoming
northwest. Seas 1 foot or less. Nearshore waters smooth. Scattered
showers and isolated thunderstorms.
.TONIGHT...Northwest to north winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.TUESDAY...Northwest winds 5 to 10 knots, increasing to near 10
knots. Seas 1 foot or less, building to around 1 foot. Nearshore
waters smooth to a light chop, becoming a light chop. Scattered
showers and isolated thunderstorms.
.TUESDAY NIGHT...Northwest winds near 10 knots. Seas around 1
foot. Nearshore waters a light chop. Scattered showers and
isolated thunderstorms.
.WEDNESDAY...West winds near 10 knots. Seas 1 to 2 feet.
Nearshore waters a light chop. Scattered showers and isolated
thunderstorms.
.WEDNESDAY NIGHT...West winds near 10 knots. Seas 1 to 2 feet.
Nearshore waters a light chop. Scattered showers and isolated
thunderstorms.
.THURSDAY...Southwest to west winds 5 to 10 knots. Seas 1 to
2 feet. Nearshore waters smooth to a light chop. Scattered
showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds 5 to 10 knots. Seas
around 1 foot. Nearshore waters smooth to a light chop. Scattered
showers and isolated thunderstorms.
.FRIDAY...South winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.FRIDAY NIGHT...East to southeast winds near 5 knots. Seas 1 foot
or less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ052>055-072>075-182045-
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-
431 AM EDT Mon Aug 18 2025

.TODAY...East winds near 5 knots, becoming northwest. Seas 1 to 2
feet. Wave Detail: Northeast to east 1 foot at 3 seconds.
Isolated showers and thunderstorms.
.TONIGHT...Northwest winds near 5 knots. Seas 1 to 2 feet. Wave
Detail: Northeast 1 foot at 4 seconds. Isolated showers and
thunderstorms.
.TUESDAY...Northwest winds 5 to 10 knots. Seas 1 to 2 feet. Wave
Detail: Northwest 1 foot at 2 seconds and northeast 1 foot at
5 seconds. Scattered showers and isolated thunderstorms.
.TUESDAY NIGHT...West to northwest winds near 10 knots. Seas 1 to
2 feet. Scattered showers and isolated thunderstorms.
.WEDNESDAY...West winds near 10 knots. Seas 1 to 2 feet.
Scattered showers and isolated thunderstorms.
.WEDNESDAY NIGHT...Southwest to west winds near 10 knots. Seas 1
to 2 feet, except 2 to 3 feet in the eastern Straits of Florida
due to northeast swell. Scattered showers and isolated
thunderstorms.
.THURSDAY...Southwest to west winds 5 to 10 knots. Seas 1 to
2 feet. Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...West to northwest winds near 5 knots. Seas 1 to
2 feet. Scattered showers and isolated thunderstorms.
.FRIDAY...Southeast to south winds near 5 knots. Seas 1 foot or
less. Scattered showers and isolated thunderstorms.
.FRIDAY NIGHT...East to southeast winds 5 to 10 knots. Seas 1 to
2 feet. Scattered showers and isolated thunderstorms.

$$

GMZ033-034-182045-
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-
431 AM EDT Mon Aug 18 2025

.TODAY...East to southeast winds near 5 knots, becoming northwest.
Seas 1 foot or less. Scattered showers and isolated
thunderstorms.
.TONIGHT...Northwest winds 5 to 10 knots. Seas 1 foot or less.
Scattered showers and isolated thunderstorms.
.TUESDAY...Northwest to north winds 5 to 10 knots. Seas 1 foot or
less. Wave Detail: Northwest to north 1 foot at 3 seconds.
Scattered showers and isolated thunderstorms.
.TUESDAY NIGHT...Northwest winds 5 to 10 knots. Seas around
1 foot. Scattered showers and isolated thunderstorms.
.WEDNESDAY...West to northwest winds near 10 knots. Seas around
1 foot. Scattered showers and isolated thunderstorms.
.WEDNESDAY NIGHT...West winds 5 to 10 knots. Seas around 1 foot.
Scattered showers and isolated thunderstorms.
.THURSDAY...Southwest to west winds 5 to 10 knots. Seas around
1 foot. Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest winds near 5 knots. Seas 1 foot or
less. Scattered showers and isolated thunderstorms.
.FRIDAY...South to southwest winds near 5 knots. Seas 1 foot or
less. Scattered showers and isolated thunderstorms.
.FRIDAY NIGHT...Southeast to south winds near 5 knots. Seas
1 foot or less. Scattered showers and isolated thunderstorms.

$$