140
FZUS52 KKEY 130811
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
411 AM EDT Thu Aug 13 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.

GMZ005-132015-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
411 AM EDT Thu Aug 13 2026

.SYNOPSIS...A high pressure system in the central North Atlantic
will continue to slide eastward and weaken today. Gentle east to
southeast breezes will slacken, becoming light and variable this
afternoon. As the high restrengthens and builds westward, breezes
will somewhat freshen for Friday through the weekend. A weak
frontal boundary will approach the Florida Peninsula early next
week, allowing breezes to slacken once again, becoming light and
variable at times.

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.

$$

GMZ031-132015-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
411 AM EDT Thu Aug 13 2026

.TODAY...East to southeast winds near 5 knots. Bay waters smooth.
A chance of showers with a slight chance of thunderstorms.
.TONIGHT...East to southeast 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 and thunderstorms.
.FRIDAY...East winds near 10 knots, increasing to 10 to 15 knots.
Bay waters a light chop, becoming a light to moderate chop. A
chance of showers and thunderstorms.
.FRIDAY NIGHT...East to southeast winds near 15 knots. Bay waters
a moderate chop. A chance of showers and thunderstorms.
.SATURDAY...East to southeast winds 10 to 15 knots, decreasing to
near 10 knots. Bay waters a light to moderate chop, becoming a
light chop. A chance of showers and thunderstorms.
.SATURDAY NIGHT...East to southeast winds 10 to 15 knots. Bay
waters a light to moderate chop. A slight chance of showers and
thunderstorms.
.SUNDAY...East to southeast winds near 10 knots. Bay waters a
light chop.
.SUNDAY NIGHT...East winds 10 to 15 knots, decreasing to near 10
knots. Bay waters a light to moderate chop, becoming a light
chop.
.MONDAY...East to southeast winds 5 to 10 knots. Bay waters
smooth to a light chop. A slight chance of showers and
thunderstorms.
.MONDAY NIGHT...Northeast to east winds 5 to 10 knots. Bay waters
smooth to a light chop, becoming smooth. A slight chance of
showers.

$$

GMZ032-035-132015-
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-
411 AM EDT Thu Aug 13 2026

.TODAY...East to southeast winds near 5 knots, becoming variable.
Seas 1 foot or less. Nearshore waters smooth. A chance of showers
with a slight chance of thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots, becoming east
to southeast and 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. A slight chance of showers and
thunderstorms.
.FRIDAY...East to southeast winds near 10 knots, increasing to 10
to 15 knots. Seas around 1 foot, building to 1 to 2 feet.
Nearshore waters a light to moderate chop. A chance of showers and
thunderstorms.
.FRIDAY NIGHT...East to southeast winds near 15 knots. Seas
1 to 2 feet, except around 2 feet west of the Marquesas Keys.
Nearshore waters a moderate chop. A chance of showers and
thunderstorms.
.SATURDAY...East to southeast 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 chance of showers and
thunderstorms.
.SATURDAY NIGHT...East to southeast winds 10 to 15 knots. Seas
1 to 2 feet. Nearshore waters a light to moderate chop. A chance
of showers with a slight chance of thunderstorms.
.SUNDAY...East to southeast winds 10 to 15 knots. Seas 1 to 2
feet. Nearshore waters a light to moderate chop.
.SUNDAY NIGHT...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.
.MONDAY...East to southeast winds 5 to 10 knots. Seas around 1
foot. Nearshore waters smooth to a light chop. A slight chance of
showers and thunderstorms.
.MONDAY NIGHT...Northeast to east winds 5 to 10 knots. Seas
1 foot or less. Nearshore waters smooth to a light chop. A slight
chance of showers and thunderstorms.

$$

GMZ042>044-132015-
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-
411 AM EDT Thu Aug 13 2026

.TODAY...East to southeast winds near 5 knots, becoming variable.
Seas around 1 foot. Nearshore waters smooth. A slight chance of
showers and thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots, becoming east
to southeast and increasing to near 10 knots. Seas around 1 foot,
building to 1 to 2 feet. Nearshore waters smooth to a light chop.
becoming a light chop. A slight chance of showers and
thunderstorms.
.FRIDAY...East winds near 10 knots, increasing to 10 to 15 knots.
Seas 1 to 2 feet, building to around 2 feet. Nearshore waters a
light chop, becoming a light to moderate chop. A chance of showers
and thunderstorms.
.FRIDAY NIGHT...East to southeast winds near 15 knots. Seas 2 to
3 feet. Nearshore waters a moderate chop. A chance of showers and
thunderstorms.
.SATURDAY...East to southeast winds 10 to 15 knots, decreasing to
near 10 knots. Seas 2 to 3 feet, subsiding to around 2 feet.
Nearshore waters a light to moderate chop, becoming a light chop.
A chance of showers and thunderstorms.
.SATURDAY NIGHT...East to southeast winds 10 to 15 knots. Seas
around 2 feet. Nearshore waters a light to moderate chop. A
slight chance of showers and thunderstorms.
.SUNDAY...East to southeast winds 10 to 15 knots. Seas around 2
feet. Nearshore waters a light to moderate chop.
.SUNDAY NIGHT...East to southeast winds 10 to 15 knots, decreasing
to near 10 knots. Seas around 2 feet. Nearshore waters a light to
moderate chop, becoming a light chop.
.MONDAY...East to southeast winds 5 to 10 knots. Seas 1 to 2
feet. Nearshore waters smooth to a light chop. A slight chance of
showers.
.MONDAY NIGHT...Northeast to east winds 5 to 10 knots. Seas
around 1 foot. Nearshore waters smooth to a light chop. A slight
chance of showers and thunderstorms.

$$

GMZ052>055-072>075-132015-
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-
411 AM EDT Thu Aug 13 2026

.TODAY...East to southeast winds 5 to 10 knots, becoming
variable. Seas 1 to 2 feet. Wave Detail: East to southeast 1 foot
at 4 seconds. A slight chance of showers and thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots, becoming east to
southeast and increasing to near 10 knots. Seas 1 to 2 feet,
building to around 2 feet. Wave Detail: East 2 feet at 4 seconds.
A slight chance of showers and thunderstorms.
.FRIDAY...East winds near 10 knots, increasing to 10 to 15 knots.
Seas around 2 feet, building to 2 to 3 feet. Wave Detail: East 2
feet at 4 seconds. A chance of showers and thunderstorms.
.FRIDAY NIGHT...East to southeast winds near 15 knots. Seas 2 to
4 feet, occasionally to 5 feet. A chance of showers and
thunderstorms.
.SATURDAY...East to southeast winds 10 to 15 knots, decreasing to
near 10 knots. Seas 2 to 4 feet, occasionally to 5 feet, subsiding
to 2 to 3 feet. A chance of showers and thunderstorms.
.SATURDAY NIGHT...East to southeast winds 10 to 15 knots. Seas 2
to 3 feet. A slight chance of showers and thunderstorms.
.SUNDAY...East to southeast winds 10 to 15 knots, decreasing to
near 10 knots. Seas 2 to 3 feet.
.SUNDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.
.MONDAY...East winds 10 to 15 knots, decreasing to near 10 knots.
Seas 2 to 3 feet, subsiding to around 2 feet.
.MONDAY NIGHT...Northeast to east winds 5 to 10 knots. Seas 1 to
2 feet. A slight chance of showers.

$$

GMZ033-034-132015-
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-
411 AM EDT Thu Aug 13 2026

.TODAY...Northeast to east winds near 5 knots, becoming variable.
Seas 1 foot or less. Wave Detail: Northwest to north 1 foot at 3
seconds. A chance of showers with a slight chance of thunderstorms.
.TONIGHT...Northeast to east winds 5 to 10 knots, becoming east
to southeast and increasing to near 10 knots. Seas around 1 foot.
A slight chance of showers and thunderstorms.
.FRIDAY...Northeast to to east winds 5 to 10 knots. Seas around 1
foot. Wave Detail: East to southeast 1 foot at 3 seconds. A
chance of showers and thunderstorms.
.FRIDAY NIGHT...East winds near 10 knots, increasing to 10 to 15
knots. Seas 1 to 2 feet, building to around 2 feet. A chance of
showers and thunderstorms.
.SATURDAY...East to southeast winds near 10 knots. Seas around 2
feet. A chance of showers and thunderstorms.
.SATURDAY NIGHT...East to southeast winds near 10 knots,
increasing to 10 to 15 knots. Seas around 2 feet, building to 2
to 3 feet. A chance of showers with a slight chance of
thunderstorms.
.SUNDAY...East to southeast winds near 10 knots, decreasing to 5
to 10 knots. Seas around 2 feet, subsiding to 1 to 2 feet. A
chance of thunderstorms with a slight chance of showers.
.SUNDAY NIGHT...East to southeast winds 5 to 10 knots. Seas 1 to
2 feet.
.MONDAY...Northeast to east winds 5 to 10 knots. Seas 1 to 2 feet.
A slight chance of showers.
.MONDAY NIGHT...North to northeast winds 5 to 10 knots. Seas
around 1 foot. A slight chance of showers and thunderstorms.

$$

BT