242
FZMY50 PGUM 201901
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
501 AM ChST Mon Sep 21 2026

Marianas Waters out to 40 nautical miles

PMZ150-210915-
501 AM ChST Mon Sep 21 2026

.Synopsis for Marianas Waters...
Light to gentle winds will prevail through midweek, then could
become occasionally moderate from midweek through the second half
of the week. Seas of 4 to 6 feet will slowly subside, dropping a
foot or so by midweek. Deep southwesterly monsoon flow will keep
the risk of scattered showers and isolated thunderstorms in the
forecast for the next several days, with the highest potential at
night.

$$

PMZ151-152-210915-
Guam Coastal Waters-Rota Coastal Waters-
501 AM ChST Mon Sep 21 2026

.TODAY...Southeast wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail:
Southwest 3 ft at 8 seconds, north 3 ft at 9 seconds and
northeast 3 ft at 11 seconds. Scattered showers with isolated
thunderstorms.
.TONIGHT...South wind 5 to 10 kt. Seas around 5 ft. Wave Detail:
Southwest 3 ft at 8 seconds, north 3 ft at 9 seconds, northeast
3 ft at 11 seconds and south 2 ft at 4 seconds. Scattered showers
with isolated thunderstorms.
.TUESDAY...Southeast wind 5 to 10 kt. Seas around 5 ft. Wave
Detail: Southwest 3 ft at 8 seconds, northeast 3 ft at
10 seconds, southeast 2 ft at 4 seconds and north 2 ft at
9 seconds. Scattered showers with isolated thunderstorms.
.TUESDAY NIGHT...South wind 10 to 15 kt. Seas around 5 ft. Wave
Detail: Northeast 3 ft at 9 seconds, north 3 ft at 9 seconds and
south 2 ft at 4 seconds. Scattered showers with isolated
thunderstorms.
.WEDNESDAY THROUGH FRIDAY...West wind 5 to 15 kt. Seas 3 to 5 ft.
Wave Detail: South 3 ft at 4 seconds, north 3 ft at 9 seconds,
northeast 3 ft at 10 seconds and west 2 ft at 8 seconds. A chance
of showers with a slight chance of thunderstorms.

$$

PMZ153-154-210915-
Tinian Coastal Waters-Saipan Coastal Waters-
501 AM ChST Mon Sep 21 2026

.TODAY...East wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail: North
3 ft at 9 seconds, northeast 3 ft at 11 seconds, southeast 2 ft
at 4 seconds and southwest 2 ft at 8 seconds. Scattered showers
with isolated thunderstorms.
.TONIGHT...Southeast wind 10 kt. Seas around 5 ft. Wave Detail:
North 3 ft at 9 seconds, northeast 3 ft at 11 seconds, southeast
2 ft at 4 seconds and southwest 2 ft at 8 seconds.
.TUESDAY...Southeast wind 10 kt. Seas around 5 ft. Wave Detail:
Northeast 3 ft at 10 seconds, southeast 2 ft at 4 seconds,
southwest 2 ft at 8 seconds and north 2 ft at 9 seconds.
Scattered showers with isolated thunderstorms.
.TUESDAY NIGHT...Southeast wind 10 kt. Seas 4 to 5 ft. Wave
Detail: Northeast 3 ft at 9 seconds, north 3 ft at 9 seconds and
southeast 2 ft at 4 seconds. Scattered showers with isolated
thunderstorms.
.WEDNESDAY...Southeast wind 5 to 15 kt. Seas 3 to 5 ft. Wave
Detail: North 3 ft at 9 seconds, northeast 3 ft at 10 seconds and
southeast 2 ft at 4 seconds. A chance of showers with isolated
thunderstorms.
.THURSDAY AND FRIDAY...Southwest to west wind 5 to 10 kt. Seas
around 3 ft. Wave Detail: North 3 ft at 8 seconds, southwest 2 ft
at 4 seconds and northeast 2 ft at 9 seconds. A chance of showers.

$$