593
FZUS52 KCHS 200537
CWFCHS

Coastal Waters Forecast
National Weather Service Charleston SC
137 AM EDT Wed Aug 20 2025

South Santee River SC to Savannah GA out 20 NM and Savannah GA to
Altamaha Sound GA out 60 NM, including Charleston Harbor and
Grays Reef National Marine Sanctuary

AMZ300-201815-
137 AM EDT Wed Aug 20 2025

.Synopsis for the coastal waters of south coastal South Carolina
and north coastal Georgia...
Weak high pressure will continue to build into the region as
Hurricane Erin passes well offshore. The pattern may become more
unsettled again late week and into this weekend as cold front
stalls nearby.

$$

AMZ330-201815-
Charleston Harbor-
137 AM EDT Wed Aug 20 2025

.TODAY...N winds 10 to 15 kt with gusts to 20 kt. A slight chance
of showers and tstms this afternoon.
.TONIGHT...N winds 10 kt. A slight chance of showers and tstms in
the evening.
.THU...NW winds 10 kt.
.THU NIGHT...W winds 5 to 10 kt. A chance of showers and tstms.
.FRI...NE winds 5 to 10 kt, becoming E 10 to 15 kt in the
afternoon. A chance of showers and tstms in the morning, then
showers and tstms likely in the afternoon.
.FRI NIGHT...E winds 5 to 10 kt. Showers and tstms likely, mainly
in the evening.
.SAT...E winds 5 to 10 kt. Showers likely with a chance of tstms.
.SAT NIGHT...E winds 5 to 10 kt. A chance of showers and tstms.
.SUN...NE winds 5 to 10 kt. A chance of showers and tstms.
.SUN NIGHT...SW winds 5 to 10 kt. A chance of showers and tstms.

Winds and waves higher in and near tstms.

Unless otherwise noted, waves 1 foot or less.

Charleston Harbor water temperature 85 degrees.

$$

AMZ350-201815-
Waters from South Santee River to Edisto Beach SC out 20 NM-
137 AM EDT Wed Aug 20 2025

...SMALL CRAFT ADVISORY IN EFFECT THROUGH FRIDAY AFTERNOON...

.TODAY...NE winds 15 to 20 kt with gusts to 25 kt. Seas 8 to
10 ft, building to 9 to 11 ft this afternoon. Wave Detail: SE
9 ft at 15 seconds, becoming SE 10 ft at 15 seconds. A slight
chance of tstms this morning. A chance of showers. A chance of
tstms this afternoon.
.TONIGHT...N winds 15 to 20 kt with gusts to 25 kt. Seas 9 to
13 ft, building to 10 to 14 ft after midnight. Wave Detail: SE
11 ft at 16 seconds and SE 7 ft at 8 seconds, becoming SE 11 ft
at 16 seconds and SE 8 ft at 8 seconds. A slight chance of
showers and tstms in the evening.
.THU...NW winds 15 to 20 kt, becoming W 10 to 15 kt in the
afternoon. Seas 9 to 11 ft, subsiding to 6 to 8 ft in the
afternoon. Wave Detail: SE 11 ft at 15 seconds and SE 6 ft at
7 seconds, becoming E 8 ft at 13 seconds.
.THU NIGHT...SW winds 10 kt, becoming W after midnight. Seas 5 to
7 ft, subsiding to 4 to 5 ft after midnight. Wave Detail: E 6 ft
at 12 seconds, becoming E 5 ft at 12 seconds. A chance of showers
and tstms.
.FRI...E winds 10 to 15 kt. Seas 3 to 4 ft. Wave Detail: E 4 ft
at 12 seconds. Showers likely. A chance of tstms in the morning,
then tstms likely in the afternoon.
.FRI NIGHT...E winds 10 to 15 kt. Seas 3 to 4 ft. Wave Detail: E
4 ft at 13 seconds and SE 1 foot at 8 seconds. Showers likely.
Tstms likely, mainly in the evening.
.SAT...E winds 10 kt. Seas 3 to 4 ft. Showers likely with a
chance of tstms.
.SAT NIGHT...E winds 5 to 10 kt. Seas 3 to 4 ft. A chance of
showers and tstms.
.SUN...NE winds 5 to 10 kt. Seas 3 to 4 ft. A chance of showers
and tstms.
.SUN NIGHT...SW winds 5 to 10 kt. Seas 2 to 3 ft. A chance of
showers and tstms.

Winds and seas higher in and near tstms.

$$

AMZ352-201815-
Waters from Edisto Beach SC to Savannah GA out 20 NM-
137 AM EDT Wed Aug 20 2025

...SMALL CRAFT ADVISORY IN EFFECT THROUGH FRIDAY AFTERNOON...

.TODAY...N winds 15 to 20 kt, diminishing to 10 to 15 kt this
afternoon. Seas 7 to 9 ft. Wave Detail: SE 9 ft at 15 seconds. A
slight chance of showers late this morning. A slight chance of
showers and tstms early this afternoon.
.TONIGHT...N winds 10 to 15 kt. Seas 8 to 10 ft, building to 9 to
11 ft after midnight. Wave Detail: SE 9 ft at 16 seconds,
becoming SE 10 ft at 16 seconds and SE 6 ft at 8 seconds.
.THU...NW winds 10 to 15 kt with gusts to 20 kt, becoming W 5 to
10 kt in the afternoon. Seas 9 to 11 ft, subsiding to 6 to 8 ft
in the afternoon. Wave Detail: SE 10 ft at 15 seconds and SE 6 ft
at 7 seconds, becoming E 8 ft at 14 seconds. A slight chance of
showers and tstms in the afternoon.
.THU NIGHT...SW winds 5 to 10 kt. Seas 5 to 6 ft, subsiding to
4 to 6 ft after midnight. Wave Detail: E 6 ft at 13 seconds,
becoming E 5 ft at 12 seconds. A chance of showers and tstms.
.FRI...NE winds 5 to 10 kt, becoming E in the afternoon. Seas
4 to 5 ft, subsiding to 3 to 4 ft in the afternoon. Wave Detail:
E 5 ft at 12 seconds, becoming E 4 ft at 12 seconds. A chance of
tstms. Showers.
.FRI NIGHT...E winds 10 to 15 kt, diminishing to 5 to 10 kt after
midnight. Seas 3 to 4 ft. Wave Detail: E 4 ft at 12 seconds.
Showers. Tstms likely, mainly in the evening.
.SAT...E winds 5 to 10 kt. Seas 3 ft. Showers likely with a
chance of tstms.
.SAT NIGHT...E winds 5 to 10 kt. Seas 3 ft. Showers likely with a
chance of tstms.
.SUN...N winds 5 to 10 kt. Seas 3 ft. A chance of showers and
tstms.
.SUN NIGHT...SW winds 5 to 10 kt. Seas 2 to 3 ft. A chance of
showers and tstms.

Winds and seas higher in and near tstms.

$$

AMZ354-201815-
Waters from Savannah GA to Altamaha Sound GA out 20 NM, including
Grays Reef National Marine Sanctuary-
137 AM EDT Wed Aug 20 2025

...SMALL CRAFT ADVISORY IN EFFECT THROUGH FRIDAY AFTERNOON...

.TODAY...N winds 15 to 20 kt, diminishing to 10 to 15 kt late.
Seas 7 to 9 ft. Wave Detail: SE 8 ft at 16 seconds. A slight
chance of showers late this morning and early afternoon.
.TONIGHT...NW winds 10 kt. Seas 7 to 9 ft, building to 8 to 10 ft
after midnight. Wave Detail: SE 8 ft at 15 seconds, becoming SE
8 ft at 16 seconds and E 6 ft at 8 seconds. A slight chance of
showers and tstms in the evening.
.THU...NW winds 10 to 15 kt, becoming W 5 to 10 kt in the
afternoon. Seas 8 to 10 ft, subsiding to 6 to 8 ft in the
afternoon. Wave Detail: E 8 ft at 15 seconds and E 5 ft at
7 seconds, becoming E 7 ft at 14 seconds and E 5 ft at 7 seconds.
A slight chance of showers and tstms in the afternoon.
.THU NIGHT...SW winds 10 kt. Seas 5 to 7 ft, subsiding to 4 to
6 ft after midnight. Wave Detail: E 6 ft at 13 seconds, becoming
E 6 ft at 12 seconds. A chance of showers and tstms.
.FRI...NW winds 5 to 10 kt, becoming E in the afternoon. Seas
4 to 5 ft. Wave Detail: E 5 ft at 12 seconds. Showers likely with
a chance of tstms in the morning, then showers with tstms likely
in the afternoon.
.FRI NIGHT...SE winds 5 to 10 kt. Seas 3 to 4 ft. Wave Detail: E
4 ft at 12 seconds. Showers. Tstms likely, mainly in the evening.
.SAT...E winds 5 to 10 kt. Seas 3 to 4 ft. Showers with tstms
likely.
.SAT NIGHT...E winds 5 to 10 kt. Seas 3 ft. Showers likely with a
chance of tstms.
.SUN...N winds 5 to 10 kt. Seas 3 ft. Showers likely with a
chance of tstms.
.SUN NIGHT...SW winds 5 to 10 kt. Seas 3 ft. A chance of showers
and tstms.

Winds and seas higher in and near tstms.

$$

AMZ374-201815-
Waters from Savannah GA to Altamaha Sound GA from 20 to 60 NM-
137 AM EDT Wed Aug 20 2025

...SMALL CRAFT ADVISORY IN EFFECT THROUGH SATURDAY MORNING...

.TODAY...N winds 15 to 20 kt with gusts to 25 kt. Seas 9 to
11 ft, building to 9 to 12 ft this afternoon. Wave Detail: E
10 ft at 15 seconds, becoming SE 10 ft at 15 seconds. A chance of
showers and tstms, mainly this morning.
.TONIGHT...NW winds 10 to 15 kt with gusts to 20 kt. Seas 9 to
12 ft. Wave Detail: E 11 ft at 16 seconds.
.THU...NW winds 10 to 15 kt. Seas 9 to 11 ft, subsiding to 7 to
9 ft in the afternoon. Wave Detail: E 11 ft at 15 seconds,
becoming E 9 ft at 13 seconds. A slight chance of showers and
tstms in the afternoon.
.THU NIGHT...SW winds 10 kt. Seas 6 to 8 ft. Wave Detail: E 8 ft
at 12 seconds. A chance of tstms. A chance of showers in the
evening, then showers likely after midnight.
.FRI...NW winds 10 kt, becoming E in the afternoon. Seas 5 to
7 ft, subsiding to 4 to 6 ft in the afternoon. Wave Detail: E
7 ft at 12 seconds, becoming E 6 ft at 12 seconds. A chance of
tstms. Showers.
.FRI NIGHT...SE winds 5 to 10 kt. Seas 4 to 6 ft, subsiding to
4 to 5 ft after midnight. Wave Detail: E 5 ft at 12 seconds and
SE 1 foot at 8 seconds, becoming E 5 ft at 13 seconds and SE
1 foot at 8 seconds. Showers. Tstms likely, mainly in the
evening.
.SAT...E winds 5 to 10 kt. Seas 4 to 5 ft. Showers with a chance
of tstms.
.SAT NIGHT...SE winds 5 to 10 kt. Seas 4 to 5 ft. Showers likely
with a chance of tstms.
.SUN...NW winds 5 to 10 kt. Seas 4 to 5 ft. Showers likely with a
chance of tstms.
.SUN NIGHT...SW winds 5 to 10 kt. Seas 3 to 4 ft. A chance of
showers and tstms.

Winds and seas higher in and near tstms.

$$