815
FZCA52 TJSJ 170800
CWFSJU

Coastal Waters Forecast
National Weather Service San Juan PR
400 AM AST Thu Sep 17 2026

Puerto Rico and the U.S. Virgin Islands Waters

Seas are provided as a range of the average height of the highest
1/3 of the waves...along with the occasional height of the average
highest 10 percent of the waves.

AMZ700-172200-
400 AM AST Thu Sep 17 2026

.Synopsis for Puerto Rico and the U.S. Virgin Islands Waters...

A departing tropical wave will continue to promote showers and
thunderstorms today into tonight, producing locally hazardous marine
conditions, including wind gusts, frequent lightning, reduced
visibility, and higher seas. A surface high pressure system over the
western Atlantic will then dominate the regional weather pattern,
yielding moderate to locally fresh easterly winds. Mariners should
remain alert, as conditions could rapidly deteriorate in and around
stronger thunderstorms.

$$

AMZ711-172200-
Atlantic Waters of Puerto Rico and USVI from 10 NM to 19.5N-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet at
6 seconds and northeast 1 foot at 13 seconds. Isolated
thunderstorms. Numerous showers early this morning, then scattered
showers late this morning and afternoon.
.TONIGHT...East winds 10 to 15 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: East 4 feet at
7 seconds and northeast 1 foot at 12 seconds. Scattered showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 20 knots. Seas
around 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
7 seconds and north 2 feet at 9 seconds.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 25 knots.
Seas around 4 feet, occasionally to 5 feet. Wave Detail: East 3 feet
at 7 seconds and north 2 feet at 9 seconds. Scattered showers.
.SATURDAY...East winds 10 to 15 knots. Seas 3 to 4 feet,
occasionally to 5 feet. Wave Detail: East 3 feet at 7 seconds and
north 2 feet at 8 seconds. Scattered showers in the morning.
.SATURDAY NIGHT...East winds 10 to 15 knots with gusts up to
20 knots. Seas around 3 feet. Wave Detail: East 3 feet at 7 seconds
and north 2 feet at 8 seconds. Scattered showers after midnight.
.SUNDAY...East winds 10 to 15 knots. Seas around 3 feet. Scattered
showers in the morning.
.SUNDAY NIGHT...East winds 10 to 15 knots. Seas around 3 feet.
Scattered showers.
.MONDAY...East winds 10 to 15 knots. Seas around 3 feet. Scattered
showers.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas around 3 feet.
Scattered showers.

Winds and seas higher in and near thunderstorms.

$$

AMZ712-172200-
Coastal Waters of Northern Puerto Rico out 10 NM-
400 AM AST Thu Sep 17 2026

.TODAY...East winds 10 to 15 knots with gusts up to 25 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds and northeast 1 foot at 14 seconds. Isolated
thunderstorms. Isolated showers this morning, then numerous showers
this afternoon.
.TONIGHT...East winds 10 to 15 knots with gusts up to 20 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
7 seconds and northeast 1 foot at 13 seconds. Numerous showers,
mainly in the evening.
.FRIDAY...East winds 10 to 15 knots, increasing to 15 to 20 knots in
the afternoon. Seas 3 to 4 feet, occasionally to 5 feet. Wave
Detail: East 4 feet at 6 seconds and northeast 1 foot at 12 seconds.
Scattered showers in the afternoon.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 25 knots,
diminishing to 5 to 10 knots after midnight. Seas 3 to 5 feet,
occasionally to 6 feet. Wave Detail: East 4 feet at 6 seconds and
north 2 feet at 9 seconds. Scattered showers in the evening, then
numerous showers after midnight.
.SATURDAY...East winds 5 to 10 knots, increasing to 10 to 15 knots
with gusts up to 25 knots in the afternoon. Seas 3 to 4 feet,
occasionally to 5 feet. Wave Detail: East 3 feet at 7 seconds and
north 2 feet at 8 seconds. Scattered showers.
.SATURDAY NIGHT...East winds 10 to 15 knots with gusts up to
20 knots, becoming southeast 5 to 10 knots after midnight. Seas
around 3 feet. Wave Detail: Northeast 3 feet at 7 seconds and
northeast 1 foot at 11 seconds. Scattered showers.
.SUNDAY...East winds 10 to 15 knots. Seas around 3 feet. Scattered
showers in the afternoon.
.SUNDAY NIGHT...East winds 5 to 10 knots. Seas around 3 feet.
.MONDAY...Southeast winds 5 to 10 knots, becoming east 10 to
15 knots in the afternoon. Seas 2 to 3 feet. Scattered showers in
the morning.
.MONDAY NIGHT...East winds 10 to 15 knots, diminishing to 5 to
10 knots after midnight. Seas around 3 feet. Scattered showers.

Winds and seas higher in and near thunderstorms.

$$

AMZ716-172200-
Coastal Waters from Cabo San Juan to the waters between Anegada
Island and Virgin Gorda and North 10 NM-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds and northeast 1 foot at 12 seconds. Isolated
thunderstorms.
.TONIGHT...East winds 10 to 15 knots with gusts up to 20 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds and northeast 1 foot at 13 seconds.
.FRIDAY...East winds 10 to 15 knots with gusts up to 20 knots. Seas
2 to 4 feet, occasionally to 5 feet. Wave Detail: East 3 feet at
6 seconds and northeast 1 foot at 12 seconds. Scattered showers in
the morning.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 2 to 3 feet. Wave Detail: East 3 feet at 5 seconds and north
2 feet at 9 seconds. Scattered showers.
.SATURDAY...East winds around 10 knots. Seas 2 to 3 feet. Wave
Detail: East 2 feet at 6 seconds and north 2 feet at 8 seconds.
Scattered showers.
.SATURDAY NIGHT...East winds around 10 knots. Seas 2 to 3 feet. Wave
Detail: East 2 feet at 6 seconds and north 2 feet at 8 seconds.
Scattered showers.
.SUNDAY...East winds around 10 knots. Seas 2 to 3 feet. Scattered
showers.
.SUNDAY NIGHT...East winds around 10 knots. Seas 2 to 3 feet.
.MONDAY...Southeast winds around 10 knots. Seas 2 to 3 feet.
Scattered showers in the morning.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.

Winds and seas higher in and near thunderstorms.

$$

AMZ723-172200-
Anegada Passage east of Virgin Gorda and Saint Croix south to 17N-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet at
7 seconds and north 1 foot at 12 seconds. Isolated thunderstorms.
.TONIGHT...East winds 10 to 15 knots with gusts up to 25 knots. Seas
around 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds and northeast 1 foot at 12 seconds. Scattered showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 20 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds and northeast 1 foot at 12 seconds. Scattered showers in
the morning.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 3 feet
at 6 seconds and northeast 1 foot at 12 seconds. Scattered showers.
.SATURDAY...East winds around 10 knots. Seas around 3 feet. Wave
Detail: East 3 feet at 5 seconds and northeast 1 foot at 11 seconds.
Scattered showers.
.SATURDAY NIGHT...East winds around 10 knots. Seas 2 to 3 feet. Wave
Detail: East 2 feet at 6 seconds and northeast 1 foot at 11 seconds.
Scattered showers.
.SUNDAY...East winds around 10 knots. Seas 2 to 3 feet. Scattered
showers in the morning.
.SUNDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.
.MONDAY...East winds 10 to 15 knots. Seas around 3 feet.
.MONDAY NIGHT...East winds around 15 knots. Seas around 3 feet.

Winds and seas higher in and near thunderstorms.

$$

AMZ726-172200-
Coastal waters east of Puerto Rico, around Vieques, and around and
just north of Culebra and Saint John-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
3 to 5 feet, occasionally to 6 feet. Wave Detail: East 4 feet at
6 seconds. Isolated thunderstorms. Scattered showers this morning,
then numerous showers this afternoon.
.TONIGHT...East winds 10 to 15 knots with gusts up to 20 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
6 seconds. Scattered showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 20 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 3 feet at
6 seconds. Scattered showers in the morning.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots.
Seas around 3 feet. Wave Detail: East 3 feet at 6 seconds. Scattered
showers.
.SATURDAY...East winds around 10 knots. Seas 2 to 3 feet. Wave
Detail: East 3 feet at 6 seconds. Scattered showers.
.SATURDAY NIGHT...East winds around 10 knots. Seas 2 to 3 feet. Wave
Detail: East 2 feet at 6 seconds. Scattered showers.
.SUNDAY...East winds around 10 knots. Seas 2 to 3 feet. Scattered
showers.
.SUNDAY NIGHT...East winds around 10 knots. Seas 2 to 3 feet.
.MONDAY...East winds around 10 knots. Seas 2 to 3 feet.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.

Winds and seas higher in and near thunderstorms.

$$

AMZ733-172200-
Caribbean waters of Puerto Rico from 10 NM to 17N, including the
coastal waters of Saint Croix-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet at
7 seconds. Isolated thunderstorms. Scattered showers this morning,
then numerous showers this afternoon.
.TONIGHT...East winds around 15 knots with gusts up to 25 knots.
Seas 4 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet
at 7 seconds. Numerous showers, mainly in the evening.
.FRIDAY...East winds 15 to 20 knots, diminishing to 10 to 15 knots
in the afternoon. Seas 4 to 5 feet, occasionally to 6 feet. Wave
Detail: East 4 feet at 6 seconds. Scattered showers in the morning.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 25 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet
at 6 seconds. Scattered showers after midnight.
.SATURDAY...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet
at 6 seconds. Scattered showers in the morning.
.SATURDAY NIGHT...East winds 10 to 15 knots with gusts up to
20 knots. Seas 2 to 3 feet. Wave Detail: East 3 feet at 6 seconds.
.SUNDAY...East winds 10 to 15 knots. Seas 2 to 3 feet. Scattered
showers in the morning.
.SUNDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.
.MONDAY...East winds 10 to 15 knots. Seas around 3 feet. Scattered
showers in the afternoon.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas around 3 feet.
Scattered showers.

Winds and seas higher in and near thunderstorms.

$$

AMZ735-172200-
Coastal Waters of Southern Puerto Rico out 10 NM-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 10 to 15 knots, increasing to 15 to 20 knots
late this morning and early afternoon, then diminishing to 10 to
15 knots late. Seas 3 to 4 feet, occasionally to 5 feet. Wave
Detail: East 4 feet at 6 seconds. Scattered showers with isolated
thunderstorms.
.TONIGHT...East winds 10 to 15 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: East 4 feet at
7 seconds. Numerous showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 25 knots. Seas
3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet at
7 seconds. Scattered showers in the morning.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet
at 6 seconds.
.SATURDAY...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 3 feet
at 6 seconds.
.SATURDAY NIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet. Wave
Detail: East 3 feet at 6 seconds. Scattered showers in the evening.
.SUNDAY...East winds 10 to 15 knots. Seas 2 to 3 feet.
.SUNDAY NIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet.
.MONDAY...East winds 10 to 15 knots. Seas 2 to 3 feet.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas 2 to 3 feet.

Winds and seas higher in and near thunderstorms.

$$

AMZ741-172200-
Mona Passage Southward to 17N-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 15 to 20 knots with gusts up to 25 knots. Seas
3 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet at
6 seconds. Isolated thunderstorms this morning. Scattered showers
until late afternoon, then numerous showers with isolated
thunderstorms late.
.TONIGHT...East winds 15 to 20 knots with gusts up to 25 knots. Seas
4 to 5 feet, occasionally to 6 feet. Wave Detail: Southeast 5 feet
at 7 seconds. Numerous showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 25 knots. Seas
3 to 5 feet, occasionally to 6 feet. Wave Detail: East 5 feet at
7 seconds. Scattered showers in the afternoon.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 4 to 5 feet, occasionally to 6 feet. Wave Detail: East 4 feet
at 7 seconds and north 2 feet at 9 seconds. Scattered showers in the
evening.
.SATURDAY...East winds 10 to 15 knots with gusts up to 20 knots.
Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail: East 4 feet
at 7 seconds and north 2 feet at 8 seconds. Scattered showers.
.SATURDAY NIGHT...East winds 10 to 15 knots with gusts up to
20 knots. Seas 3 to 4 feet, occasionally to 5 feet. Wave Detail:
East 3 feet at 7 seconds.
.SUNDAY...East winds 10 to 15 knots. Seas around 3 feet.
.SUNDAY NIGHT...East winds 10 to 15 knots. Seas around 3 feet.
Scattered showers.
.MONDAY...East winds 10 to 15 knots. Seas 3 to 4 feet, occasionally
to 5 feet. Scattered showers.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas 3 to 4 feet,
occasionally to 5 feet. Scattered showers.

Winds and seas higher in and near thunderstorms.

$$

AMZ742-172200-
Coastal Waters of Northwestern Puerto Rico out 10 NM-
400 AM AST Thu Sep 17 2026

.TODAY...East winds 5 to 10 knots, increasing to 10 to 15 knots with
gusts up to 25 knots late this morning and afternoon. Seas 2 to
3 feet. Wave Detail: Southeast 3 feet at 5 seconds. Showers with
isolated thunderstorms this afternoon.
.TONIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet. Wave Detail:
East 3 feet at 5 seconds and northeast 1 foot at 13 seconds.
Scattered showers in the evening.
.FRIDAY...East winds 5 to 10 knots. Seas 2 to 3 feet. Wave Detail:
East 3 feet at 6 seconds and north 1 foot at 9 seconds. Numerous
showers in the afternoon.
.FRIDAY NIGHT...East winds 10 to 15 knots with gusts up to 20 knots,
diminishing to around 5 knots after midnight. Seas 2 to 3 feet. Wave
Detail: East 3 feet at 6 seconds and north 2 feet at 9 seconds.
Scattered showers in the evening.
.SATURDAY...East winds around 5 knots. Seas 2 to 3 feet. Wave
Detail: East 2 feet at 6 seconds and north 2 feet at 8 seconds.
Numerous showers in the afternoon.
.SATURDAY NIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet. Wave
Detail: Northeast 3 feet at 7 seconds. Scattered showers in the
evening.
.SUNDAY...East winds around 5 knots. Seas 2 to 3 feet. Numerous
showers in the afternoon.
.SUNDAY NIGHT...East winds around 5 knots. Seas 2 to 3 feet.
.MONDAY...East winds around 5 knots. Seas around 2 feet. Scattered
showers in the afternoon.
.MONDAY NIGHT...East winds 5 to 10 knots. Seas around 2 feet.

Winds and seas higher in and near thunderstorms.

$$

AMZ745-172200-
Coastal Waters of Southwestern Puerto Rico out 10 NM-
400 AM AST Thu Sep 17 2026

...SMALL CRAFT SHOULD EXERCISE CAUTION...

.TODAY...East winds 10 to 15 knots, becoming southeast 15 to
20 knots late this morning and afternoon. Seas 2 to 3 feet. Wave
Detail: Southeast 3 feet at 5 seconds. Isolated showers this
morning, then scattered showers with isolated thunderstorms early
this afternoon. Isolated showers late.
.TONIGHT...East winds 10 to 15 knots with gusts up to 20 knots. Seas
2 to 3 feet. Wave Detail: East 3 feet at 6 seconds. Scattered
showers.
.FRIDAY...East winds 10 to 15 knots with gusts up to 20 knots. Seas
2 to 3 feet. Wave Detail: Southeast 3 feet at 6 seconds. Scattered
showers in the afternoon.
.FRIDAY NIGHT...East winds 10 to 15 knots, diminishing to 5 to
10 knots after midnight. Seas 2 to 3 feet. Wave Detail: Southeast
2 feet at 6 seconds and north 1 foot at 9 seconds. Scattered showers
in the evening.
.SATURDAY...Southeast winds 5 to 10 knots. Seas 2 to 3 feet. Wave
Detail: Southeast 2 feet at 6 seconds and north 1 foot at 9 seconds.
.SATURDAY NIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet. Wave
Detail: Southeast 2 feet at 6 seconds and north 1 foot at 8 seconds.
.SUNDAY...Southeast winds 10 to 15 knots. Seas 2 to 3 feet.
Scattered showers in the afternoon.
.SUNDAY NIGHT...East winds 5 to 10 knots. Seas 2 to 3 feet.
.MONDAY...Southeast winds 10 to 15 knots. Seas around 2 feet.
Scattered showers in the afternoon.
.MONDAY NIGHT...East winds 10 to 15 knots. Seas around 2 feet.

Winds and seas higher in and near thunderstorms.

$$