FZMY50 PGUM 150523 CWFGUM Coastal Waters Forecast for the Mariana Islands National Weather Service Tiyan GU 323 PM ChST Thu Oct 15 2026 Marianas Waters out to 40 nautical miles PMZ150-152000- 323 PM ChST Thu Oct 15 2026 .Synopsis for Marianas Waters... A Typhoon Watch is in effect for Guam, Rota, Tinian and Saipan waters. Gentle to moderate northeasterlies will prevail across the Marianas tonight through Friday night, followed by quickly deteriorating conditions as Tropical Depression 29W makes its way across the Marianas, potentially as a Typhoon Saturday night through Sunday night. As such, seas are expected to quickly rise above 20 feet during closest passage of 29W, producing dangerous seas possibly into Monday. $$ PMZ151-152-152000- Guam Coastal Waters-Rota Coastal Waters- 323 PM ChST Thu Oct 15 2026 ...TYPHOON WATCH IN EFFECT... .TONIGHT...Northeast wind 5 to 10 kt. Seas around 4 ft. Wave Detail: Northeast 4 ft at 9 seconds and northeast 2 ft at 4 seconds. .FRIDAY...Northeast wind 10 kt. Seas 4 to 5 ft. Wave Detail: Northeast 4 ft at 8 seconds and northeast 2 ft at 4 seconds. .FRIDAY NIGHT...Northeast wind 10 to 15 kt. Seas 5 to 6 ft. Wave Detail: Northeast 5 ft at 9 seconds and northeast 3 ft at 4 seconds. Scattered showers. .SATURDAY...North to northeast wind 10 to 15 kt. Seas 5 to 7 ft. Wave Detail: Northeast 5 ft at 9 seconds and northeast 3 ft at 4 seconds. Scattered showers and isolated thunderstorms. .SATURDAY NIGHT...Northeast tropical storm force wind to 40 kt with gusts to 70 kt. Seas 9 to 14 ft. Periods of torrential rain, widespread heavy showers and scattered thunderstorms. .SUNDAY...South tropical storm force wind to 50 kt. Seas 19 to 23 ft. Periods of torrential rain, widespread heavy showers and scattered thunderstorms. .MONDAY...South tropical storm force wind to 40 kt. Seas 12 to 15 ft. A chance of showers with a slight chance of thunderstorms. .TUESDAY...South wind 15 to 25 kt. Seas 8 to 10 ft. Wave Detail: Southwest 8 ft at 8 seconds and south 6 ft at 7 seconds. A chance of showers. $$ PMZ153-154-152000- Tinian Coastal Waters-Saipan Coastal Waters- 323 PM ChST Thu Oct 15 2026 ...TYPHOON WATCH IN EFFECT... .TONIGHT...Northeast wind 5 to 15 kt. Seas around 4 to 5 ft. Wave Detail: Northeast 4 ft at 9 seconds and northeast 3 ft at 4 seconds. .FRIDAY...Northeast wind 10 to 15 kt. Seas 4 to 5 ft. Wave Detail: Northeast 4 ft at 9 seconds and northeast 3 ft at 4 seconds. .FRIDAY NIGHT...Northeast wind 10 to 15 kt. Seas 5 to 6 ft. Wave Detail: Northeast 5 ft at 9 seconds and northeast 3 ft at 5 seconds. Scattered showers. .SATURDAY...Northeast wind 15 to 20 kt with gusts to 30 kt. Seas 6 to 8 ft. Wave Detail: Northeast 6 ft at 9 seconds and northeast 4 ft at 6 seconds. Scattered showers. .SATURDAY NIGHT...Northeast tropical storm force wind to 40 kt with gusts to 55 kt. Seas 9 to 11 ft. Periods of torrential rain, widespread heavy showers and scattered thunderstorms. .SUNDAY...Southeast tropical storm force wind to 45 kt. Seas 19 to 23 ft. Periods of torrential rain, widespread heavy showers and scattered thunderstorms. .MONDAY...South tropical storm force wind to 45 kt. Seas 14 to 17 ft. Widespread heavy showers with a slight chance of thunderstorms. .TUESDAY...South wind 30 kt. Seas 8 to 10 ft. Wave Detail: South 8 ft at 8 seconds and southwest 8 ft at 9 seconds. A chance of showers. $$