738
FZMY50 PGUM 200600
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
400 PM ChST Sun Sep 20 2026

Marianas Waters out to 40 nautical miles

PMZ150-202100-
400 PM ChST Sun Sep 20 2026

.Synopsis for Marianas Waters...
Light to gentle winds will prevail through the beginning of the
week, becoming occasionally moderate around midweek. Seas of 4 to
6 feet will slowly subside, dropping a foot or so by the middle
of the week. 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.

$$

PMZ151-152-202100-
Guam Coastal Waters-Rota Coastal Waters-
400 PM ChST Sun Sep 20 2026

.TONIGHT...Southwest wind 5 kt. Seas 4 to 6 ft. Wave Detail:
Southwest 4 ft at 9 seconds, northeast 3 ft at 10 seconds and
northwest 3 ft at 10 seconds. Scattered showers with isolated
thunderstorms.
.MONDAY...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, northeast 3 ft
at 11 seconds and south 2 ft at 4 seconds. Scattered showers with
isolated thunderstorms.
.MONDAY NIGHT...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: North 3 ft at 9 seconds, northeast 3 ft at 9 seconds and
south 3 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: North 3 ft at 9 seconds, south 3 ft at 4 seconds,
northeast 3 ft at 10 seconds and west 3 ft at 8 seconds. A chance of
showers with a slight chance of thunderstorms.

$$

PMZ153-154-202100-
Tinian Coastal Waters-Saipan Coastal Waters-
400 PM ChST Sun Sep 20 2026

.TONIGHT...East wind 5 to 10 kt. Seas 5 to 6 ft. Wave Detail:
Southwest 4 ft at 9 seconds, northeast 3 ft at 10 seconds,
northwest 3 ft at 10 seconds and east 2 ft at 4 seconds.
Scattered showers with isolated thunderstorms.
.MONDAY...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, east 2 ft
at 4 seconds and southwest 2 ft at 8 seconds. Scattered showers
with isolated thunderstorms.
.MONDAY NIGHT...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: North 3 ft at 9 seconds, northeast 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 3 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.

$$