549
FZMY50 PGUM 181901
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
501 AM ChST Tue Aug 19 2025

Marianas Waters out to 40 nautical miles

PMZ150-190845-
501 AM ChST Tue Aug 19 2025

.Synopsis for Marianas Waters...A tropical disturbance passed
south of Guam overnight, producing a period of high end scattered
showers across the region, especially for Guam waters. Combined
seas of between 5 and 7 feet today are expected to diminish
through Wednesday to between 3 and 5 feet, then stay fairly
steady. Gentle to moderate winds today will diminish to light to
gentle by Wednesday then stay near these levels the rest of the
week.

$$

PMZ151-190845-
Guam Coastal Waters-
501 AM ChST Tue Aug 19 2025

.TODAY...Southeast wind 5 to 15 kt. Seas 5 to 7 ft. Wave Detail:
East 6 ft at 8 seconds and southeast 3 ft at 4 seconds. Scattered
showers with isolated thunderstorms.
.TONIGHT...Southeast wind 5 to 10 kt. Seas 4 to 5 ft. Wave
Detail: East 5 ft at 8 seconds and southeast 2 ft at 4 seconds.
Scattered showers with isolated thunderstorms.
.WEDNESDAY...East wind 5 to 10 kt. Seas 3 to 4 ft. Wave Detail:
East 4 ft at 8 seconds. Isolated thunderstorms.
.WEDNESDAY NIGHT...Northeast wind 5 to 10 kt. Seas 3 to 4 ft.
Wave Detail: East 3 ft at 8 seconds and northeast 2 ft at
4 seconds. Isolated thunderstorms.
.THURSDAY THROUGH FRIDAY...East wind 5 to 10 kt. Seas 3 to 4 ft.
Wave Detail: East 3 ft at 8 seconds and northeast 2 ft at
4 seconds. A chance of showers with a slight chance of
thunderstorms.
.SATURDAY...East wind 5 to 10 kt. Seas around 3 ft. Wave Detail:
East 2 ft at 4 seconds and east 2 ft at 8 seconds. A slight chance
of thunderstorms.

$$

PMZ152>154-190845-
Rota Coastal Waters-Tinian Coastal Waters-Saipan Coastal Waters-
501 AM ChST Tue Aug 19 2025

.TODAY...Southeast wind 5 to 15 kt with occasional gusts to 25
kt. Seas 5 to 7 ft. Wave Detail: East 6 ft at 8 seconds and
southeast 3 ft at 4 seconds. Scattered showers this morning.
Isolated thunderstorms.
.TONIGHT...Southeast wind 5 to 10 kt. Seas 4 to 6 ft. Wave
Detail: East 5 ft at 8 seconds and southeast 2 ft at 4 seconds.
Scattered showers with isolated thunderstorms.
.WEDNESDAY...East wind 5 to 10 kt. Seas around 4 ft. Wave Detail:
East 4 ft at 8 seconds and east 2 ft at 4 seconds. Isolated
thunderstorms.
.WEDNESDAY NIGHT...East wind 5 to 10 kt. Seas 3 to 4 ft. Wave
Detail: East 3 ft at 8 seconds and east 2 ft at 4 seconds.
Isolated thunderstorms.
.THURSDAY THROUGH FRIDAY...East wind 5 to 10 kt. Seas 3 to 4 ft.
Wave Detail: East 3 ft at 8 seconds and east 2 ft at 4 seconds. A
slight chance of thunderstorms.
.SATURDAY...East wind 10 kt. Seas around 3 ft. Wave Detail: East
2 ft at 4 seconds and east 2 ft at 8 seconds. A chance of showers
with a slight chance of thunderstorms.

$$