334
FZMY50 PGUM 011646
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
246 AM ChST Fri Oct 2 2026

Marianas Waters out to 40 nautical miles

PMZ150-020830-
246 AM ChST Fri Oct 2 2026

.Synopsis for Marianas Waters...
Strong to gale force southwesterlies will continue. Combined seas
of 9 to 12 ft will rapidly increase to as high as 20 ft today as
Tropical Storm Choi- wan (26W) crosses the northern CNMI and
brings elevated southwest monsoon swell to the Marianas. For
Saipan and Tinian, a Tropical Storm Warning remains in effect. For
Guam and Rota, a Gale Warning remains in effect. Mariners should
continue monitoring the forecast for changes in the coming days.

$$

PMZ151-152-020830-
Guam Coastal Waters-Rota Coastal Waters-
246 AM ChST Fri Oct 2 2026

...SMALL CRAFT ADVISORY IN EFFECT THROUGH EARLY THIS MORNING...
...GALE WARNING IN EFFECT THROUGH SATURDAY AFTERNOON...
...HAZARDOUS SEAS WATCH IN EFFECT FROM SATURDAY AFTERNOON THROUGH
SUNDAY AFTERNOON...

.TODAY...Southwest gale force wind to 35 kt with gusts to 45 kt.
Seas 8 to 10 ft, building to 12 to 14 ft. Numerous locally heavy
showers with isolated thunderstorms.
.TONIGHT...Southwest gale force wind to 35 kt with gusts to 45
kt. Seas 13 to 16 ft. Scattered showers with isolated
thunderstorms. Locally heavy showers possible.
.SATURDAY...Southwest wind 30 kt with gusts to 40 kt. Seas 14 to
17 ft. Scattered showers with isolated thunderstorms.
.SATURDAY NIGHT...Southwest wind 30 kt with gusts to 40 kt. Seas
13 to 16 ft. Scattered showers with isolated thunderstorms.
.SUNDAY...Southwest wind 30 kt. Seas 13 to 16 ft. Scattered
showers with isolated thunderstorms.
.MONDAY...Southwest wind 20 to 25 kt. Seas 11 to 14 ft. A chance
of showers with a slight chance of thunderstorms.
.TUESDAY...Southwest wind 10 to 20 kt. Seas 8 to 10 ft. Wave
Detail: West 8 ft at 9 seconds, southwest 5 ft at 7 seconds and
northwest 3 ft at 13 seconds. A slight chance of thunderstorms.

$$

PMZ153-154-020830-
Tinian Coastal Waters-Saipan Coastal Waters-
246 AM ChST Fri Oct 2 2026

...TROPICAL STORM WARNING IN EFFECT...

.TODAY...Southwest tropical storm force wind to 40 kt with gusts
to 55 kt. Seas 11 to 13 ft, building to 14 to 16 ft. Widespread
locally heavy showers and scattered thunderstorms.
.TONIGHT...Southwest tropical storm force wind to 40 kt with
gusts to 55 kt. Seas 16 to 19 ft. Widespread showers with
isolated thunderstorms.
.SATURDAY...Southwest tropical storm force wind to 35 kt with
gusts to 50 kt. Seas 17 to 20 ft. Numerous showers with isolated
thunderstorms.
.SATURDAY NIGHT...Southwest tropical storm force wind to 35 kt
with gusts to 45 kt. Seas 16 to 19 ft. Scattered showers with
isolated thunderstorms.
.SUNDAY...Southwest wind 30 kt. Seas 14 to 17 ft. Scattered
showers with isolated thunderstorms.
.MONDAY...Southwest wind 20 to 25 kt. Seas 12 to 15 ft. Scattered
showers with a slight chance of thunderstorms.
.TUESDAY...Southwest wind 10 to 20 kt. Seas 8 to 10 ft. Wave
Detail: West 9 ft at 9 seconds, southwest 5 ft at 7 seconds and
northwest 3 ft at 13 seconds. A chance of showers with a slight
chance of thunderstorms.

$$