Coastal Waters Forecast
Issued by NWS Tiyan, Guam

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499
FZMY50 PGUM 290600
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
400 PM ChST Sun Jun 29 2025

Marianas Waters out to 40 nautical miles

PMZ150-292100-
400 PM ChST Sun Jun 29 2025

.Synopsis for Marianas Waters...A developing monsoon disturbance
to the northeast of the islands will keep a wet southwesterly
pattern across the Marianas. Combined seas of 4 to 5 feet look to
increase a foot or two Monday into Tuesday as a southwest monsoon
swell and winds build into the region.

$$

PMZ151-152-292100-
Guam Coastal Waters-Rota Coastal Waters-
400 PM ChST Sun Jun 29 2025

.TONIGHT...South wind 10 kt. Seas 3 to 5 ft. Wave Detail: East 4
ft at 8 seconds and south 2 ft at 4 seconds. Isolated
thunderstorms. Scattered showers becoming numerous near midnight.
Locally heavy showers possible.
.MONDAY...South wind 10 to 15 kt. Seas 4 to 6 ft. Wave Detail:
East 4 ft at 8 seconds, south 3 ft at 4 seconds and southwest 3
ft at 8 seconds. Numerous showers with isolated thunderstorms.
Locally heavy showers possible.
.MONDAY NIGHT...Southwest wind 10 to 15 kt. Seas 5 to 6 ft. Wave
Detail: East 4 ft at 8 seconds, southwest 3 ft at 5 seconds and
southwest 3 ft at 8 seconds. Numerous showers with isolated
thunderstorms. Locally heavy showers possible.
.TUESDAY...Southwest wind 10 to 15 kt. Seas 5 to 6 ft. Wave
Detail: East 4 ft at 8 seconds, west 4 ft at 8 seconds and
southwest 3 ft at 4 seconds. Numerous showers with isolated
thunderstorms.
.TUESDAY NIGHT...Southwest wind 10 to 15 kt. Seas 4 to 6 ft. Wave
Detail: Southwest 4 ft at 8 seconds, east 3 ft at 8 seconds and
southwest 3 ft at 4 seconds. Scattered showers with isolated
thunderstorms.
.WEDNESDAY THROUGH FRIDAY...South wind 5 to 15 kt. Seas 4 to
5 ft. Wave Detail: East 4 ft at 8 seconds, southwest 3 ft at 8
seconds and southwest 3 ft at 4 seconds. A chance of showers with
a slight chance of thunderstorms.

$$

PMZ153-154-292100-
Tinian Coastal Waters-Saipan Coastal Waters-
400 PM ChST Sun Jun 29 2025

.TONIGHT...South wind 5 to 10 kt. Seas 3 to 5 ft. Wave Detail:
East 4 ft at 8 seconds and south 2 ft at 4 seconds. Isolated
thunderstorms. Scattered showers near midnight.
.MONDAY...South wind 10 to 15 kt. Seas 4 to 6 ft. Wave Detail:
East 4 ft at 8 seconds, west 3 ft at 8 seconds and south 3 ft at
4 seconds. Numerous showers with isolated thunderstorms.
.MONDAY NIGHT...South wind 10 to 15 kt. Seas 5 to 6 ft. Wave
Detail: East 4 ft at 8 seconds, south 3 ft at 5 seconds and west
3 ft at 8 seconds. Numerous showers with isolated thunderstorms.
.TUESDAY...Southwest wind 15 to 20 kt. Seas 5 to 6 ft. Wave
Detail: East 4 ft at 8 seconds, west 4 ft at 8 seconds and
southwest 3 ft at 5 seconds. Numerous showers with isolated
thunderstorms.
.TUESDAY NIGHT...Southwest wind 15 kt. Seas 4 to 6 ft. Wave
Detail: West 4 ft at 8 seconds, southwest 3 ft at 5 seconds and
east 3 ft at 8 seconds. Scattered showers with isolated
thunderstorms.
.WEDNESDAY THROUGH FRIDAY...South wind 5 to 15 kt. Seas 4 to
5 ft. Wave Detail: Southwest 3 ft at 8 seconds, southwest 3 ft at
5 seconds and east 3 ft at 8 seconds. A chance of showers with a
slight chance of thunderstorms.

$$