887
FZUS52 KKEY 190817
CWFKEY

Coastal Waters Forecast for the Florida Keys
National Weather Service Key West FL
417 AM EDT Tue Aug 19 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.

GMZ005-192030-
Synopsis for Keys coastal waters from Ocean Reef to Dry Tortugas
417 AM EDT Tue Aug 19 2025

.SYNOPSIS...Major Hurricane Erin will turn due northward over the
open Atlantic over the course of today. The increasingly
expansive circulation of Erin will result in a transition from
light to gentle northerly breezes across Florida Keys coastal
waters overnight, to gentle to moderate northwest breezes Tuesday
and moderate to fresh westerly breezes on Wednesday. A slight
swell from the north will lead to elevated seas in northern
portions of the Florida Straits. As Hurricane Erin migrates
farther away toward the north and northeast, a weak subtropical
high pressure ridge will settle over Florida Keys coastal waters,
resulting in a lighter wind pattern Thursday through Saturday.

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.

$$

GMZ031-192030-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
417 AM EDT Tue Aug 19 2025

.TODAY...North winds 5 to 10 knots, becoming west to northwest.
Bay waters smooth to a light chop. Scattered showers and isolated
thunderstorms.
.TONIGHT...Northwest to north winds 5 to 10 knots, becoming west
to northwest and increasing to near 10 knots. Bay waters smooth
to a light chop, becoming a light chop. Scattered showers and
isolated thunderstorms.
.WEDNESDAY...West to northwest winds near 10 knots, becoming west
and increasing to 15 to 20 knots. Bay waters a light chop,
becoming choppy. Scattered showers and thunderstorms.
.WEDNESDAY NIGHT...West winds 15 to 20 knots, becoming southwest
to west and decreasing to 10 to 15 knots. Bay waters choppy,
becoming a light to moderate chop. Scattered showers and
thunderstorms.
.THURSDAY...Southwest to west winds 10 to 15 knots, decreasing to
near 10 knots. Bay waters a light to moderate chop, becoming a
light chop. Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...West winds decreasing to 5 to 10 knots. Bay
waters becoming smooth to a light chop. Scattered showers and
isolated thunderstorms.
.FRIDAY...Southwest to west winds 5 to 10 knots. Bay waters
smooth to a light chop. Scattered showers and isolated
thunderstorms.
.FRIDAY NIGHT...West to northwest winds near 5 knots. Bay waters
smooth. Scattered showers and isolated thunderstorms.
.SATURDAY...Southwest to west winds near 5 knots, becoming
variable. Bay waters smooth. Scattered showers and isolated
thunderstorms.
.SATURDAY NIGHT...Variable winds near 5 knots. Bay waters smooth.
Scattered showers and isolated thunderstorms.

$$

GMZ032-035-192030-
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-
417 AM EDT Tue Aug 19 2025

.TODAY...North winds 5 to 10 knots, becoming west to northwest and
increasing to 10 to 15 knots. Seas 1 foot or less, building to 1
to 2 feet. Nearshore waters smooth to a light chop, becoming a
light to moderate chop late. Scattered showers and isolated
thunderstorms.
.TONIGHT...Northwest to north winds 10 to 15 knots, becoming west
to northwest. Seas 1 to 2 feet. Nearshore waters a light to
moderate chop. Scattered showers and isolated thunderstorms.
.WEDNESDAY...West to northwest winds 10 to 15 knots, becoming west
and increasing to near 15 knots. Seas 1 to 2 feet. Nearshore
waters a light to moderate chop, becoming a moderate chop.
Scattered showers and thunderstorms.
.WEDNESDAY NIGHT...West winds near 15 knots, decreasing to 10 to
15 knots. Seas 1 to 2 feet. Nearshore waters a moderate chop,
becoming a light to moderate chop. Scattered showers and
thunderstorms.
.THURSDAY...Southwest to west 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.
Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds decreasing to 5 to 10
knots. Seas around 1 foot. Nearshore waters becoming smooth to a
light chop. Scattered showers and isolated thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.FRIDAY NIGHT...West to northwest winds near 5 knots. Seas 1 foot
or less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.SATURDAY...West winds near 5 knots, becoming variable. Seas 1
foot or less. Nearshore waters smooth. Scattered showers and
isolated thunderstorms.
.SATURDAY NIGHT...Variable winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ042-192030-
Hawk Channel from Ocean Reef to Craig Key out to the reef-
417 AM EDT Tue Aug 19 2025

.TODAY...Northwest to north winds 5 to 10 knots, becoming
northwest. Seas 1 to 2 feet. Nearshore waters smooth to a light
chop. Scattered showers and isolated thunderstorms.
.TONIGHT...Northwest winds 5 to 10 knots, increasing to near 10
knots. Seas 1 to 2 feet. Nearshore waters smooth to a light chop,
becoming a light chop. Scattered showers and isolated
thunderstorms.
.WEDNESDAY...West to northwest winds 10 to 15 knots, becoming
southwest to west and increasing to 15 to 20 knots. Seas 1 to 3
feet. Nearshore waters a light to moderate chop, becoming choppy.
Scattered showers and thunderstorms.
.WEDNESDAY NIGHT...Southwest to west winds 15 to 20 knots,
becoming west and decreasing to 10 to 15 knots. Seas 1 to 3 feet.
Nearshore waters choppy, becoming a light to moderate chop.
Scattered showers and thunderstorms.
.THURSDAY...Southwest to west winds 10 to 15 knots. Seas 1 to
2 feet. Nearshore waters a light to moderate chop. Scattered
showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds near 10 knots, becoming
west and decreasing to 5 to 10 knots. Seas 1 to 2 feet. Nearshore
waters a light chop, becoming smooth to a light chop. Scattered
showers and isolated thunderstorms.
.FRIDAY...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 NIGHT...West winds decreasing to near 5 knots. Seas
subsiding to 1 foot or less. Nearshore waters smooth. Scattered
showers and isolated thunderstorms.
.SATURDAY...Southwest to west winds near 5 knots, becoming
variable. Seas 1 foot or less. Nearshore waters smooth. Scattered
showers and isolated thunderstorms.
.SATURDAY NIGHT...Variable winds near 5 knots. Seas 1 foot or less.
Nearshore waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ043-044-192030-
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-
417 AM EDT Tue Aug 19 2025

.TODAY...Northwest to north winds 5 to 10 knots, becoming
northwest. Seas around 1 foot. Nearshore waters smooth to a light
chop. Scattered showers and isolated thunderstorms.
.TONIGHT...Northwest to north winds 5 to 10 knots, becoming
northwest 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. Scattered showers and isolated
thunderstorms.
.WEDNESDAY...West to northwest winds increasing to 10 to 15
knots. Seas building to 1 to 2 feet. Nearshore waters becoming a
light to moderate chop. Scattered showers and thunderstorms.
.WEDNESDAY NIGHT...West 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. Scattered
showers and thunderstorms.
.THURSDAY...Southwest to west winds near 10 knots. Seas around
1 foot. Nearshore waters 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...Southwest to west winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.FRIDAY NIGHT...West to northwest winds near 5 knots. Seas 1 foot
or less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.
.SATURDAY...West winds near 5 knots, becoming variable. Seas 1
foot or less. Nearshore waters smooth. Scattered showers and
isolated thunderstorms.
.SATURDAY NIGHT...Variable winds near 5 knots. Seas 1 foot or
less. Nearshore waters smooth. Scattered showers and isolated
thunderstorms.

$$

GMZ052-072-192030-
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-
417 AM EDT Tue Aug 19 2025

.TODAY...Northwest to north winds 5 to 10 knots, becoming
northwest. Seas 1 to 2 feet, building to 2 to 3 feet due to a
northerly swell. Wave Detail: North to northeast 2 feet at 4
seconds and east 1 foot at 15 seconds. Scattered showers and
isolated thunderstorms.
.TONIGHT...West to northwest winds 5 to 10 knots, increasing to 10
to 15 knots. Seas 2 to 3 feet due to northerly swell. Wave
Detail: North to northeast 2 feet at 5 seconds and west to
northwest 1 foot at 3 seconds. Scattered showers and isolated
thunderstorms.
.WEDNESDAY...West to northwest winds 10 to 15 knots, becoming west
and increasing to 15 to 20 knots in the afternoon. Seas 2 to 3
feet, building to 2 to 4 feet, occasionally 5 feet due to
northerly swell. Wave Detail: West 3 feet at 4 seconds and north
to northeast 2 feet at 6 seconds. Scattered showers and
thunderstorms.
.WEDNESDAY NIGHT...Southwest to west winds 15 to 20 knots,
decreasing to 10 to 15 knots late. Seas 2 to 4 feet, occasionally
to 5 feet due to northerly swell. Scattered showers and
thunderstorms.
.THURSDAY...Southwest to west winds 10 to 15 knots. Seas subsiding
to 2 to 3 feet. Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds 5 to 10 knots. Seas
2 to 3 feet. Scattered showers and isolated thunderstorms.
.FRIDAY...Southwest to west winds 5 to 10 knots. Seas 1 to
2 feet. Isolated showers and thunderstorms.
.FRIDAY NIGHT...West winds near 5 knots. Seas 1 to 2 feet.
Isolated showers and thunderstorms.
.SATURDAY...West winds near 5 knots, becoming variable. Seas 1 to
2 feet. Isolated showers and thunderstorms.
.SATURDAY NIGHT...Variable winds 5 to 10 knots. Seas 1 to 2 feet.
Isolated showers and thunderstorms.

$$

GMZ053>055-073>075-192030-
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-
417 AM EDT Tue Aug 19 2025

.TODAY...Northwest winds 5 to 10 knots. Seas 1 to 2 feet. Wave
Detail: Northeast 1 foot at 3 seconds. Scattered showers and
isolated thunderstorms.
.TONIGHT...Northwest winds 5 to 10 knots, increasing to 10 to 15
knots. Seas 1 to 2 feet. Wave Detail: North 1 foot at 4 seconds.
Scattered showers and isolated thunderstorms.
.WEDNESDAY...West to northwest winds 10 to 15 knots. Seas 1 to
2 feet. Wave Detail: West to northwest 2 feet at 3 seconds and
northeast to east 1 foot at 5 seconds. Scattered showers and
thunderstorms.
.WEDNESDAY NIGHT...West winds 10 to 15 knots, becoming southwest
to west and decreasing to near 10 knots late. Seas 1 to 2 feet.
Scattered showers and thunderstorms.
.THURSDAY...Southwest to west winds near 10 knots, decreasing to 5
to 10 knots. Seas 1 to 2 feet, subsiding to around 1 foot.
Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds near 5 knots. Seas
around 1 foot. Isolated showers and thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots, becoming variable.
Seas around 1 foot. Isolated showers and thunderstorms.
.FRIDAY NIGHT AND SATURDAY...Variable winds near 5 knots. Seas
around 1 foot. Isolated showers and thunderstorms.
.SATURDAY NIGHT...Variable winds 5 to 10 knots. Seas around 1
foot. Isolated showers and thunderstorms.

$$

GMZ033-034-192030-
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-
417 AM EDT Tue Aug 19 2025

.TODAY...North winds 5 to 10 knots, becoming northwest and increasing
to 10 to 15 knots. Seas around 1 foot, building to 1 to 2 feet.
Wave Detail: Northwest to north 1 foot at 3 seconds. Scattered
showers and isolated thunderstorms.
.TONIGHT...Northwest to north winds 10 to 15 knots. Seas 1 to 2
feet. Wave Detail: Northwest to north 2 feet at 4 seconds.
Scattered showers and isolated thunderstorms.
.WEDNESDAY...West to northwest winds 10 to 15 knots, becoming west
and increasing to near 15 knots. Seas 1 to 2 feet. Wave Detail:
West to northwest 2 feet at 4 seconds. Scattered showers and
thunderstorms.
.WEDNESDAY NIGHT...West winds near 15 knots, decreasing to 10 to
15 knots. Seas 1 to 2 feet. Scattered showers and thunderstorms.
.THURSDAY...Southwest to west winds 10 to 15 knots, decreasing to
near 10 knots. Seas 1 to 2 feet, subsiding to around 1 foot.
Scattered showers and isolated thunderstorms.
.THURSDAY NIGHT...Southwest to west winds 5 to 10 knots. Seas
around 1 foot. Scattered showers and isolated thunderstorms.
.FRIDAY...Southwest to west winds near 5 knots. Seas around
1 foot. Scattered showers and isolated thunderstorms.
.FRIDAY NIGHT AND SATURDAY...West winds near 5 knots. Seas 1 foot
or less. Scattered showers and isolated thunderstorms.
.SATURDAY NIGHT...Variable winds near 5 knots. Seas around 1
foot. Scattered showers and isolated thunderstorms.

$$

DP