865
FZUS52 KKEY 212021
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
421 PM EDT Thu Aug 21 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.

GMZ005-220830-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
421 PM EDT Thu Aug 21 2025

.SYNOPSIS...Hurricane Erin will continue a northeast movement
away from the Eastern Seaboard and out into the North Atlantic
while accelerating. A slight swell from the north will continue to
lead to elevated seas in eastern portions of the Florida Straits
for another day or two. A weak subtropical high pressure ridge
will begin to build into the Keys tonight before settling over the
Keys through the weekend. This will result in generally light,
occasionally light to gentle breezes.

The Approximate Shoreward Edge of the Gulf Stream as of August 21...

20 NM South of Dry Tortugas Light...on Loggerhead Key.
 9 NM South of Cosgrove Shoal Light...off the Marquesas Keys.
 9 NM South of Sand Key Light...off Key West.
13 NM South of Looe Key...off Big Pine Key.
17 NM Southeast of Sombrero Key Light...off Marathon.
17 NM Southeast of Alligator Reef Light...off Islamorada.
13 NM Southeast of Molasses Reef Light...off Key Largo.
 5 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.

$$

GMZ031-220830-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest to west winds near 10 knots, decreasing to 5
to 10 knots. Bay waters a light chop, becoming smooth to a light
chop. Isolated showers and thunderstorms.
.FRIDAY...Southwest to west winds 5 to 10 knots. Bay waters
smooth to a light chop. Isolated showers and thunderstorms.
.FRIDAY NIGHT...West winds near 5 knots. Bay waters smooth.
Isolated showers and thunderstorms.
.SATURDAY...South to southwest winds near 5 knots, becoming
southwest to west and increasing to 5 to 10 knots. Bay waters
smooth, becoming smooth to a light chop. Scattered showers and
isolated thunderstorms.
.SATURDAY NIGHT...West winds 5 to 10 knots, becoming variable and
decreasing to near 5 knots. Bay waters smooth to a light chop,
becoming smooth. Isolated showers and thunderstorms.
.SUNDAY...Southwest to west winds near 5 knots. Bay waters
smooth. Isolated showers and thunderstorms.
.SUNDAY NIGHT...Southwest to west winds near 5 knots. Bay waters
smooth. Isolated showers and thunderstorms.
.MONDAY...Southwest winds near 5 knots. Bay waters smooth.
Isolated showers and thunderstorms.
.MONDAY NIGHT...West to northwest winds near 5 knots. Bay waters
smooth. Isolated showers and thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Bay waters
smooth. Isolated showers and thunderstorms.
.TUESDAY NIGHT...Northeast winds near 5 knots. Bay waters smooth.
Isolated showers and thunderstorms.

$$

GMZ032-035-220830-
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-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest to west winds 5 to 10 knots, decreasing to
near 5 knots. Seas 1 foot or less. Nearshore waters smooth to a
light chop, becoming smooth. Isolated showers and thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.FRIDAY NIGHT...Southwest to west winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.SATURDAY...Southwest winds near 5 knots, increasing to 5 to 10
knots. Seas 1 foot or less. Nearshore waters smooth, becoming
smooth to a light chop. Isolated showers and thunderstorms.
.SATURDAY NIGHT...West to northwest winds 5 to 10 knots, becoming
variable and decreasing to near 5 knots. Seas 1 foot or less.
Nearshore waters smooth to a light chop, becoming smooth. Isolated
showers and thunderstorms.
.SUNDAY...Southwest to west winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.SUNDAY NIGHT...West to northwest winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.MONDAY...Variable winds near 5 knots, becoming west. Seas 1 foot
or less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.MONDAY NIGHT...Northwest to north winds near 5 knots. Seas
1 foot or less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas
1 foot or less. Nearshore waters smooth. Isolated showers and
thunderstorms.

$$

GMZ042-220830-
Hawk Channel from Ocean Reef to Craig Key out to the reef-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest winds near 10 knots, decreasing to 5 to 10
knots. Seas 1 to 2 feet. Nearshore waters a light chop, becoming
smooth to a light chop. Isolated showers and thunderstorms.
.FRIDAY...Southwest to west winds 5 to 10 knots. Seas 1 to 2 feet.
Nearshore waters smooth to a light chop. Isolated showers and
thunderstorms.
.FRIDAY NIGHT...West winds near 5 knots. Seas subsiding to 1 foot
or less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.SATURDAY...Southwest winds near 5 knots, increasing to 5 to 10
knots. Seas 1 foot or less, building to around 1 foot. Nearshore
waters smooth, becoming smooth to a light chop. Isolated showers
and thunderstorms.
.SATURDAY NIGHT...Southwest to west winds near 5 knots, becoming
variable. Seas subsiding to 1 foot or less. Nearshore waters
smooth. Isolated showers and thunderstorms.
.SUNDAY...Southwest to west winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.SUNDAY NIGHT...Southwest to west winds 5 to 10 knots, becoming
variable and decreasing to near 5 knots. Seas around 1 foot.
Nearshore waters smooth to a light chop, becoming smooth. Isolated
showers and thunderstorms.
.MONDAY...Variable winds near 5 knots, becoming southwest to west.
Seas 1 foot or less. Nearshore waters smooth. Isolated showers
and thunderstorms.
.MONDAY NIGHT...West to northwest winds near 5 knots. Seas 1 foot
or less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas 1
foot or less. Nearshore waters smooth. Isolated showers and
thunderstorms.

$$

GMZ043-044-220830-
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-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest to west winds near 10 knots, becoming south
to southwest 5 to 10 knots. Seas around 1 foot. Nearshore waters
a light chop, becoming smooth to a light chop. Isolated showers
and thunderstorms.
.FRIDAY...Southwest winds decreasing to near 5 knots. Seas
subsiding to 1 foot or less. Nearshore waters becoming smooth.
Isolated showers and thunderstorms.
.FRIDAY NIGHT...West winds near 5 knots, becoming variable. Seas
1 foot or less. Nearshore waters smooth. Isolated showers and
thunderstorms.
.SATURDAY...South to southwest winds near 5 knots, becoming
southwest to west. Seas 1 foot or less. Nearshore waters smooth.
Isolated showers and thunderstorms.
.SATURDAY NIGHT...Northwest to north winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.SUNDAY...South to southwest winds near 5 knots, becoming
west. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.SUNDAY NIGHT...West to northwest winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.MONDAY...Variable winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. Isolated showers and thunderstorms.
.MONDAY NIGHT...West to northwest winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Isolated
showers and thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Isolated showers and thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas 1
foot or less. Nearshore waters smooth. Isolated showers and
thunderstorms.

$$

GMZ052-072-220830-
Straits of Florida from Ocean Reef to Craig Key out 20 NM-
Straits of Florida from Ocean Reef to Craig Key 20 to 60 NM out-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest winds near 10 knots, decreasing to 5 to 10
knots. Seas 2 to 3 feet due to northerly swell. Wave Detail: North
to northeast 2 feet at 11 seconds and southwest to west 1 foot at
3 seconds. Isolated showers and thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots. Seas 1 to 3 feet
due to northerly swell. Wave Detail: North to northeast 2 feet at
11 seconds. Isolated showers and thunderstorms.
.FRIDAY NIGHT...Southwest to west winds near 5 knots. Seas 1 to
2 feet. Wave Detail: North to northeast 2 feet at 12 seconds.
Isolated showers and thunderstorms.
.SATURDAY...South to southwest winds near 5 knots. Seas 1 to 2
feet. Isolated showers and thunderstorms.
.SATURDAY NIGHT...West to northwest winds near 5 knots, becoming
variable. Seas 1 to 2 feet. Isolated showers and thunderstorms.
.SUNDAY...South to southwest winds near 5 knots. Seas 1 to 2
feet. Isolated showers and thunderstorms.
.SUNDAY NIGHT...Variable winds near 5 knots. Seas 1 to 2 feet.
Isolated showers and thunderstorms.
.MONDAY...Variable winds near 5 knots. Seas 1 to 2 feet. Isolated
showers and thunderstorms.
.MONDAY NIGHT...Variable winds near 5 knots. Seas 1 to 2 feet.
Isolated showers and thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas 1 to 2 feet.
Isolated showers and thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas 1 to
2 feet. Scattered showers and isolated thunderstorms.

$$

GMZ053>055-073>075-220830-
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 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-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest to west winds near 10 knots, becoming south
to southwest 5 to 10 knots. Seas around 1 foot. Wave Detail: West
1 foot at 3 seconds and east 1 foot at 4 seconds. Isolated
showers and thunderstorms.
.FRIDAY...South to southwest winds near 5 knots. Seas around 1
foot. Wave Detail: East to southeast 1 foot at 4 seconds. Isolated
showers and thunderstorms.
.FRIDAY NIGHT...Southwest to west winds near 5 knots. Seas around
1 foot. Wave Detail: East 1 foot at 5 seconds. Isolated showers
and thunderstorms.
.SATURDAY...Southwest to west winds near 5 knots, becoming
southwest to west in the afternoon. Seas around 1 foot. Isolated
showers and thunderstorms.
.SATURDAY NIGHT...West winds near 5 knots. Seas around 1 foot.
Isolated showers and thunderstorms.
.SUNDAY...South to southwest winds near 5 knots. Seas around 1
foot. Isolated showers and thunderstorms.
.SUNDAY NIGHT...Variable winds near 5 knots. Seas around 1 foot.
Isolated showers and thunderstorms.
.MONDAY...Variable winds near 5 knots. Seas around 1 foot.
Isolated showers and thunderstorms.
.MONDAY NIGHT...North to northeast winds near 5 knots. Seas
around 1 foot. Isolated showers and thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas around 1
foot. Isolated showers and thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas
around 1 foot. Isolated showers and thunderstorms.

$$

GMZ033-034-220830-
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-
421 PM EDT Thu Aug 21 2025

.TONIGHT...Southwest winds 5 to 10 knots, decreasing to near 5
knots. Seas around 1 foot. Wave Detail: West 1 foot at 3 seconds.
Isolated showers and thunderstorms.
.FRIDAY...Southwest winds near 5 knots. Seas around 1 foot. Wave
Detail: Southwest to west 1 foot at 3 seconds. Isolated showers
and thunderstorms.
.FRIDAY NIGHT...Southwest to west winds near 5 knots. Seas around
1 foot. Wave Detail: West 1 foot at 3 seconds. Isolated showers
and thunderstorms.
.SATURDAY...Southwest winds near 5 knots, becoming west. Seas
around 1 foot. Scattered showers and isolated thunderstorms.
.SATURDAY NIGHT...West to northwest winds near 5 knots, becoming
south to southwest. Seas around 1 foot. Isolated showers and
thunderstorms.
.SUNDAY...Southwest winds near 5 knots, becoming west. Seas
around 1 foot. Isolated showers and thunderstorms.
.SUNDAY NIGHT...West to northwest winds near 5 knots, becoming
variable. Seas 1 foot or less. Isolated showers and
thunderstorms.
.MONDAY...Variable winds near 5 knots, becoming west to northwest.
Seas 1 foot or less. Isolated showers and thunderstorms.
.MONDAY NIGHT...Northwest to north winds near 5 knots. Seas
1 foot or less. Isolated showers and thunderstorms.
.TUESDAY...North to northeast winds near 5 knots. Seas 1 foot or
less. Isolated showers and thunderstorms.
.TUESDAY NIGHT...North to northeast winds near 5 knots. Seas 1
foot or less. Isolated showers and thunderstorms.

$$