FZMY50 PGUM 161350 CWFGUM Coastal Waters Forecast for the Mariana Islands National Weather Service Tiyan GU 1150 PM ChST Fri Oct 16 2026 Marianas Waters out to 40 nautical miles PMZ150-162045- 1150 PM ChST Fri Oct 16 2026 .Synopsis for Marianas Waters... A Typhoon Warning remains in effect for Guam and Rota waters, and a Tropical Storm Warning for Tinian and Saipan waters. A Typhoon Watch remains in effect for Tinian and Saipan waters. Gentle to fresh northeasterlies will prevail across the Marianas tonight, followed by quickly deteriorating conditions as Tropical Storm Champi (29W) makes its way across the Marianas, potentially as a typhoon Saturday night through Sunday evening. As such, seas are expected to quickly rise, with significant sea heights reaching as high as 35 feet during closest passage of Champi, producing dangerous seas possibly into Monday. Isolated thunderstorms will begin Saturday. $$ PMZ151-162045- Guam Coastal Waters- 1150 PM ChST Fri Oct 16 2026 ...TYPHOON WARNING IN EFFECT... .TONIGHT...North wind 10 to 15 kt. Seas 3 to 5 ft. Wave Detail: Northeast 4 ft at 9 seconds and northeast 3 ft at 4 seconds. .SATURDAY...North wind 15 to 25 kt. Seas 4 to 6 ft becoming 7 to 9 feet in the afternoon. Wave Detail: East 6 ft at 9 seconds and north 5 ft at 5 seconds. Isolated thunderstorms. .SATURDAY NIGHT...Northeast to east tropical storm force wind to 60 kt with gusts to 80 kt. Seas 10 to 13 ft. Isolated showers and thunderstorms becoming scattered locally heavy showers and thunderstorms by midnight. Visibility 1 NM or less. .SUNDAY...Northeast typhoon force wind to 90 kt with gusts to 130 kt, turning southwest through the day. Seas 30 to 35 ft. Widespread locally heavy showers and scattered thunderstorms. Visibility 1 NM or less. .SUNDAY NIGHT...South tropical storm force wind to 60 kt with gusts to 80 kt. Seas 16 to 20 ft. Scattered locally heavy showers with isolated thunderstorms. Visibility 1 NM or less. .MONDAY...Southeast wind 15 to 25 kt with gusts to 30 kt. Seas 10 to 13 ft. A chance of showers with a slight chance of thunderstorms. .TUESDAY...East wind 10 to 15 kt. Seas 7 to 9 ft. Wave Detail: Southwest 8 ft at 8 seconds and east 3 ft at 4 seconds. .WEDNESDAY...South wind 10 kt. Seas 5 to 7 ft. Wave Detail: Northwest 7 ft at 8 seconds and south 2 ft at 4 seconds. $$ PMZ152-162045- Rota Coastal Waters- 1150 PM ChST Fri Oct 16 2026 ...TYPHOON WARNING IN EFFECT... .TONIGHT...Northeast wind 10 to 15 kt. Seas around 5 ft. Wave Detail: Northeast 4 ft at 9 seconds and northeast 3 ft at 4 seconds. .SATURDAY...North wind 15 to 25 kt. Seas 5 to 7 foot becoming 7 to 9 ft in the afternoon. Wave Detail: East 6 ft at 9 seconds and north 5 ft at 6 seconds. Isolated thunderstorms. .SATURDAY NIGHT...Southeast tropical storm force wind to 40 kt with gusts to 60 kt. Seas 13 to 16 ft. Scattered showers and thunderstorms. Visibility 1 NM or less. .SUNDAY...Southeast to south typhoon force wind to 70 kt with gusts to 100 kt. Seas 20 to 25 ft. Numerous locally heavy showers and scattered thunderstorms. Visibility 1 NM or less. .SUNDAY NIGHT...Southeast to south tropical storm force wind to 50 kt with gusts to 70 kt. Seas 16 to 19 ft. Scattered thunderstorms. .MONDAY...Southeast wind 15 to 25 kt. Seas 10 to 13 ft. A chance of showers with a slight chance of thunderstorms. Visibility 1 NM or less. .TUESDAY...East wind 10 to 15 kt. Seas 7 to 9 ft. Wave Detail: Southwest 8 ft at 9 seconds and east 3 ft at 4 seconds. A chance of showers. .WEDNESDAY...South wind 10 kt. Seas 5 to 7 ft. Wave Detail: North 7 ft at 9 seconds and southeast 2 ft at 4 seconds. $$ PMZ153-154-162045- Tinian Coastal Waters-Saipan Coastal Waters- 1150 PM ChST Fri Oct 16 2026 ...TROPICAL STORM WARNING IN EFFECT... .TONIGHT...Northeast wind 10 to 20 kt. Seas 4 to 6 ft. Wave Detail: Northeast 5 ft at 9 seconds and northeast 3 ft at 5 seconds. .SATURDAY...Northeast wind 20 to 25 kt. Seas 7 to 9 ft. Wave Detail: East 6 ft at 9 seconds and northeast 6 ft at 5 seconds. Isolated thunderstorms. .SATURDAY NIGHT...East to southeast tropical storm force wind to 40 kt with gusts to 60 kt. Seas 12 to 15 ft. Scattered locally heavy showers with isolated thunderstorms. Visibility 1 NM or less. .SUNDAY...Southeast tropical storm force wind to 50 kt with gusts to 70 kt. Seas 19 to 23 ft. Scattered locally heavy showers and thunderstorms. Visibility 1 NM or less. .SUNDAY NIGHT...Southeast tropical storm force wind 40 kt with gusts to 60 kt. Seas 14 to 17 ft. Scattered thunderstorms. Visibility 1 NM or less. .MONDAY...Southeast wind 15 to 25 kt. Seas 10 to 13 ft. A chance of showers with a slight chance of thunderstorms. .TUESDAY...East wind 10 to 15 kt. Seas 7 to 9 ft. Wave Detail: Southwest 8 ft at 9 seconds and east 4 ft at 4 seconds. A chance of showers. .WEDNESDAY...Southeast wind 10 kt. Seas 6 to 8 ft. Wave Detail: Northwest 8 ft at 9 seconds and southeast 2 ft at 4 seconds. $$