893
FZUS52 KKEY 180824
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
424 AM EDT Fri Sep 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.

GMZ005-182030-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
424 AM EDT Fri Sep 18 2026

.SYNOPSIS...
High pressure in the north Atlantic weakens today and this will
allow winds to slacken across the Florida Keys coastal waters with
winds mainly light to gentle through the remainder of the week
and into the weekend. In addition, an increasingly wet weather
pattern will continue to develop across the Florida Keys coastal
waters through early next week as an upper level low retrogrades
westward across the Florida peninsula and eventually shifts into
the Gulf this weekend. As a result, scattered to occasional
numerous showers and thunderstorms will be a daily occurence with
gusty winds, lightning strikes, blinding downpours, and locally
hazardous seas being the main hazards mariners could encounter in
the vicinity of this activity. The upper level low is forecast to
move out of the area early next week with winds becoming more
southerly and breezes remaining light to gentle. Rain chances will
also continue to remain elevated into next week as deep moisture
lingers across the Florida Keys coastal waters in the wake of the
departing weather disturbance.

The Approximate Shoreward Edge of the Gulf Stream as of
September 11, 2026...

26 NM south of Dry Tortugas Light, on Loggerhead Key
15 NM south of Cosgrove Shoal Light, off the Marquesas Keys
15 NM south of Sand Key Light, off Key West
11 NM south-southeast of Looe Key, off Big Pine Key
 8 NM southeast of Sombrero Key Light, off Marathon
 6 NM southeast of Alligator Reef Light, off Islamorada
 2 NM southeast of Molasses Reef Light, off Key Largo
 1 NM east-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.

$$

GMZ031-182030-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
424 AM EDT Fri Sep 18 2026

.TODAY...East winds near 5 knots. Bay waters smooth. Showers
likely with a chance of thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots. Bay waters
smooth to a light chop. A chance of showers and thunderstorms.
.SATURDAY...East winds near 5 knots. Bay waters smooth. A chance
of showers and thunderstorms.
.SATURDAY NIGHT...Southeast winds 5 to 10 knots. Bay waters
smooth to a light chop. A chance of showers and thunderstorms.
.SUNDAY...South winds near 5 knots. Bay waters smooth. Showers
likely with a chance of thunderstorms.
.SUNDAY NIGHT...South winds 5 to 10 knots. Bay waters smooth to a
light chop. A chance of showers and thunderstorms.
.MONDAY...South to southwest winds near 5 knots. Bay waters
smooth. Showers likely with a chance of thunderstorms.
.MONDAY NIGHT...Southeast to south winds 5 to 10 knots. Bay
waters smooth to a light chop. Showers likely with a chance of
thunderstorms.
.TUESDAY...Southeast to south winds near 5 knots. Bay waters
smooth. Showers and thunderstorms likely.
.TUESDAY NIGHT...Southeast winds 5 to 10 knots. Bay waters smooth
to a light chop. Showers likely with a chance of thunderstorms.

$$

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-
424 AM EDT Fri Sep 18 2026

.TODAY...East winds near 5 knots. Seas 1 foot or less. Nearshore
waters smooth. A chance of showers and thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Showers likely
with a chance of thunderstorms.
.SATURDAY...East winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. Showers likely with a chance of
thunderstorms.
.SATURDAY NIGHT...East winds 5 to 10 knots, becoming southeast.
Seas 1 foot or less. Nearshore waters smooth to a light chop.
Showers likely with a chance of thunderstorms.
.SUNDAY...South winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. Showers likely with a chance of
thunderstorms.
.SUNDAY NIGHT...South winds 5 to 10 knots. Seas 1 foot or less.
Nearshore waters smooth to a light chop. Showers likely with a
chance of thunderstorms.
.MONDAY...South to southwest winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Showers likely
with a chance of thunderstorms.
.MONDAY NIGHT...South winds near 5 knots, increasing to around
10 knots. Seas 1 foot or less. Nearshore waters smooth, becoming
a light chop. Showers likely with a chance of thunderstorms.
.TUESDAY...Southeast to south winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Showers and
thunderstorms likely.
.TUESDAY NIGHT...Southeast winds 5 to 10 knots. Seas 1 foot or
less. Nearshore waters smooth to a light chop. Showers likely with
a chance of thunderstorms.

$$

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-
424 AM EDT Fri Sep 18 2026

.TODAY...East winds near 5 knots. Seas around 1 foot. Nearshore
waters smooth. A chance of showers and thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots. Seas around
1 foot. Nearshore waters smooth to a light chop. A chance of
showers and thunderstorms.
.SATURDAY...East winds near 5 knots. Seas around 1 foot.
Nearshore waters smooth. A chance of showers and thunderstorms.
.SATURDAY NIGHT...East winds 5 to 10 knots, becoming southeast to
south. Seas around 1 foot. Nearshore waters smooth to a light
chop. Showers likely with a chance of thunderstorms.
.SUNDAY...South to southwest winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Showers likely with a chance of
thunderstorms.
.SUNDAY NIGHT...South winds 5 to 10 knots. Seas around 1 foot.
Nearshore waters smooth to a light chop. A chance of showers and
thunderstorms.
.MONDAY...South winds 5 to 10 knots. Seas around 1 foot.
Nearshore waters smooth to a light chop. Showers likely with a
chance of thunderstorms.
.MONDAY NIGHT...Southeast to south winds 5 to 10 knots. Seas
around 1 foot. Nearshore waters smooth to a light chop. Showers
likely with a chance of thunderstorms.
.TUESDAY...Southeast to south winds 5 to 10 knots. Seas around 1
foot. Nearshore waters smooth to a light chop. Showers likely with
a chance of thunderstorms.
.TUESDAY NIGHT...Southeast winds 5 to 10 knots. Seas around
1 foot. Nearshore waters smooth to a light chop. Showers likely
with a chance of thunderstorms.

$$

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-
424 AM EDT Fri Sep 18 2026

.TODAY...East winds near 10 knots, becoming 5 to 10 knots. Seas 1
to 2 feet. Wave Detail: East 2 feet at 5 seconds. A chance of
showers and thunderstorms.
.TONIGHT...East winds 5 to 10 knots. Seas 1 to 2 feet. Wave
Detail: Northeast to east 2 feet at 5 seconds. Showers likely
with a chance of thunderstorms.
.SATURDAY...East winds near 5 knots. Seas around 1 foot. Wave
Detail: East 1 foot at 4 seconds. A chance of showers and
thunderstorms.
.SATURDAY NIGHT...East winds 5 to 10 knots, becoming southeast to
south. Seas 1 to 2 feet. Showers likely with a chance of
thunderstorms.
.SUNDAY...South to southwest winds near 5 knots. Seas around
1 foot. Showers likely with a chance of thunderstorms.
.SUNDAY NIGHT...South winds 5 to 10 knots. Seas 1 to 2 feet. A
chance of showers and thunderstorms.
.MONDAY...South winds 5 to 10 knots. Seas 1 to 2 feet. Showers
likely with a chance of thunderstorms.
.MONDAY NIGHT...Southeast to south winds 5 to 10 knots. Seas 1 to
2 feet. Showers likely with a chance of thunderstorms.
.TUESDAY...Southeast to south winds 5 to 10 knots. Seas 1 to 2 feet.
Showers likely with a chance of thunderstorms.
.TUESDAY NIGHT...Southeast winds 5 to 10 knots. Seas 1 to 2 feet.
Showers likely with a chance of 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-
424 AM EDT Fri Sep 18 2026

.TODAY...Northeast to east winds 5 to 10 knots. Seas 1 to 2 feet.
Wave Detail: East 2 feet at 4 seconds. A chance of showers and
thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots. Seas around
1 foot. Wave Detail: Northeast to east 1 foot at 4 seconds.
Showers likely with a chance of thunderstorms.
.SATURDAY...East winds near 5 knots. Seas 1 foot or less. Wave
Detail: East 1 foot at 3 seconds. Showers likely with a chance of
thunderstorms.
.SATURDAY NIGHT...East to southeast winds 5 to 10 knots. Seas
1 around 1 foot. A chance of showers and thunderstorms.
.SUNDAY...Southeast to south winds near 5 knots. Seas 1 foot or
less. Showers likely with a chance of thunderstorms.
.SUNDAY NIGHT...South to southwest winds near 5 knots, becoming southeast
to south. Seas 1 foot or less. A chance of showers and
thunderstorms.
.MONDAY...South to southwest winds 5 to 10 knots. Seas around
1 foot. Showers likely with a chance of thunderstorms.
.MONDAY NIGHT...South winds 5 to 10 knots. Seas around 1 foot.
Showers with a chance of thunderstorms.
.TUESDAY...Southeast to south winds near 5 knots. Seas around
1 foot. Showers and thunderstorms likely.
.TUESDAY NIGHT...Southeast winds 5 to 10 knots. Seas around
1 foot. Showers likely with a chance of thunderstorms.

$$