Coastal Waters Forecast
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
974 FZMY50 PGUM 250905 AAA CWFGUM Coastal Waters Forecast for the Mariana Islands...UPDATED National Weather Service Tiyan GU 705 PM ChST Fri Jul 25 2025 Updated for the Hazardous Seas Warning issued for the CNMI waters Marianas Waters out to 40 nautical miles PMZ150-260000- 705 PM ChST Fri Jul 25 2025 .Synopsis for Marianas Waters...Recent altimetry passes are showing seas upwards of 16 feet in the coastal waters of the CNMI, which is in the Hazardous Seas criteria of 15+ feet. Have issued the Hazardous Seas Warning for Rota, Tinian and Saipan through Saturday night, with a Small Craft Advisory then in effect on Sunday. The Small Craft Advisory remains in effect for Guam through Saturday night, however, seas have been bumped up to 13 feet across the western waters based off the recent altimetry data. Conditions will begin to improve by from south to north on Sunday across Guam on Sunday and the CNMI Sunday night as Krosa and the monsoon surge lift father north. $$ PMZ151-260000- Guam Coastal Waters- 705 PM ChST Fri Jul 25 2025 ...SMALL CRAFT ADVISORY IN EFFECT THROUGH EARLY SUNDAY MORNING... .TONIGHT...Southwest wind 20 to 30 kt with gusts to 40 kt. Seas 9 to 13 ft. Wave Detail: Southwest 9 ft at 7 seconds, west 7 ft at 10 seconds and east 2 ft at 9 seconds. Numerous locally heavy showers with isolated thunderstorms. .SATURDAY...Southwest wind 20 to 30 kt with gusts to 40 kt. Seas 9 to 13 ft. Wave Detail: Southwest 9 ft at 7 seconds, west 7 ft at 10 seconds and east 2 ft at 9 seconds. Numerous locally heavy showers with isolated thunderstorms. .SATURDAY NIGHT...Southwest wind 15 to 25 kt with gusts to 35. Seas 8 to 11 ft. Wave Detail: Southwest 8 ft at 6 seconds, west 7 ft at 10 seconds and east 2 ft at 9 seconds. Scattered showers. .SUNDAY...Southwest wind 15 to 20 kt. Seas 6 to 8 ft. Wave Detail: West 7 ft at 10 seconds, southwest 5 ft at 6 seconds and east 2 ft at 9 seconds. Scattered showers with isolated thunderstorms. .SUNDAY NIGHT...Southwest wind 15 to 20 kt. Seas 5 to 7 ft. Wave Detail: West 6 ft at 10 seconds and southwest 4 ft at 5 seconds. Scattered showers. .MONDAY THROUGH WEDNESDAY...Southwest wind 10 to 20 kt. Seas 5 to 7 ft. Wave Detail: West 6 ft at 10 seconds and southwest 4 ft at 6 seconds. A slight chance of thunderstorms. $$ PMZ152>154-260000- Rota Coastal Waters-Tinian Coastal Waters-Saipan Coastal Waters- 705 PM ChST Fri Jul 25 2025 ...HAZARDOUS SEAS WARNING IN EFFECT UNTIL 6 AM CHST SUNDAY... ...SMALL CRAFT ADVISORY IN EFFECT FROM 6 AM TO 6 PM CHST SUNDAY... .TONIGHT...Southwest wind 25 to 30 kt with gusts to 40 kt. Seas 12 to 16 ft. Wave Detail: Southwest 9 ft at 7 seconds, west 9 ft at 10 seconds and east 2 ft at 9 seconds. Widespread locally heavy showers with isolated thunderstorms. .SATURDAY...Southwest wind 25 to 30 kt with gusts to 40 kt. Seas 12 to 16 ft. Wave Detail: Southwest 9 ft at 7 seconds, west 9 ft at 10 seconds and east 2 ft at 9 seconds. Widespread locally heavy showers with isolated thunderstorms. .SATURDAY NIGHT...Southwest wind 20 to 30 kt with gusts to 40 kt. Seas 10 to 15 ft. Wave Detail: Southwest 8 ft at 7 seconds, west 9 ft at 10 seconds and east 2 ft at 9 seconds. Scattered showers with isolated thunderstorms. .SUNDAY...Southwest wind 15 to 25 kt with gusts to 35 kt. Seas 8 to 11 ft. Wave Detail: West 7 ft at 10 seconds, southwest 8 ft at 6 seconds and east 2 ft at 9 seconds. Scattered showers with isolated thunderstorms. .SUNDAY NIGHT...Southwest wind 15 to 20 kt kt. Seas 7 to 9 ft. Wave Detail: West 7 ft at 10 seconds and southwest 5 ft at 6 seconds. Scattered showers with isolated thunderstorms. .MONDAY THROUGH WEDNESDAY...Southwest wind 10 to 20 kt. Seas 6 to 8 ft. Wave Detail: West 7 ft at 10 seconds and southwest 5 ft at 6 seconds. A slight chance of thunderstorms. $$