FZMY50 PGUM 221800 CWFGUM Coastal Waters Forecast for the Mariana Islands National Weather Service Tiyan GU 400 AM ChST Mon Mar 23 2026 Marianas Waters out to 40 nautical miles PMZ150-230815- 400 AM ChST Mon Mar 23 2026 .Synopsis for Marianas Waters... Elevated northeast to east swell and wind waves, and long-period north to northeast swell continue to produce hazardous seas up to 11 feet through Tuesday afternoon. Winds will be moderate to strong through Tuesday, then gradually diminishing to gentle to moderate late week. Convergence north of a tropical disturbance is expected to bring an increase in showers through Wednesday, with a higher shower coverage and thunderstorm potential for Guam and Rota through Tuesday. $$ PMZ151-152-230815- Guam Coastal Waters-Rota Coastal Waters- 400 AM ChST Mon Mar 23 2026 ...SMALL CRAFT ADVISORY IN EFFECT THROUGH TUESDAY AFTERNOON... .TODAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail: Northeast 7 ft at 8 seconds, east 5 ft at 6 seconds and northeast 3 ft at 12 seconds. Scattered showers with isolated thunderstorms. .TONIGHT...Northeast wind 15 to 20 kt with gusts to 30 kt. Seas 8 to 10 ft. Wave Detail: East 8 ft at 8 seconds, northeast 5 ft at 6 seconds and northeast 3 ft at 11 seconds. Scattered showers with isolated thunderstorms. .TUESDAY...Northeast wind 10 to 20 kt. Seas 7 to 9 ft. Wave Detail: East 7 ft at 8 seconds, northeast 4 ft at 5 seconds, north 3 ft at 10 seconds and northeast 2 ft at 11 seconds. Scattered showers with isolated thunderstorms. .TUESDAY NIGHT...Northeast wind 10 to 20 kt. Seas 6 to 8 ft. Wave Detail: East 6 ft at 8 seconds, north 4 ft at 9 seconds, northeast 3 ft at 5 seconds and northeast 2 ft at 11 seconds. Scattered showers. .WEDNESDAY...Northeast wind 10 to 20 kt. Seas 6 to 8 ft. Wave Detail: East 5 ft at 8 seconds, northeast 4 ft at 6 seconds, north 3 ft at 11 seconds and northeast 2 ft at 10 seconds. .THURSDAY...Northeast wind 10 to 20 kt. Seas 5 to 7 ft. Wave Detail: East 6 ft at 8 seconds, northeast 3 ft at 5 seconds and north 2 ft at 10 seconds. .FRIDAY...Northeast wind 10 to 15 kt. Seas 3 to 5 ft. Wave Detail: East 3 ft at 8 seconds, north 3 ft at 11 seconds and northeast 2 ft at 4 seconds. $$ PMZ153-154-230815- Tinian Coastal Waters-Saipan Coastal Waters- 400 AM ChST Mon Mar 23 2026 ...SMALL CRAFT ADVISORY IN EFFECT THROUGH TUESDAY AFTERNOON... .TODAY...Northeast wind 20 to 25 kt. Seas 8 to 10 ft. Wave Detail: Northeast 7 ft at 8 seconds, northeast 6 ft at 7 seconds and northeast 3 ft at 12 seconds. .TONIGHT...Northeast wind 20 kt with gusts to 30 kt. Seas 9 to 11 ft. Wave Detail: East 8 ft at 8 seconds, northeast 5 ft at 7 seconds and northeast 3 ft at 11 seconds. .TUESDAY...Northeast wind 20 kt. Seas 8 to 10 ft. Wave Detail: East 8 ft at 8 seconds, northeast 4 ft at 6 seconds, north 3 ft at 10 seconds and northeast 2 ft at 11 seconds. .TUESDAY NIGHT...Northeast wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail: East 6 ft at 8 seconds, northeast 4 ft at 6 seconds, north 4 ft at 9 seconds and northeast 2 ft at 11 seconds. Scattered showers. .WEDNESDAY...Northeast wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail: East 6 ft at 8 seconds, northeast 5 ft at 7 seconds, north 3 ft at 11 seconds and northeast 2 ft at 10 seconds. .THURSDAY...Northeast wind 10 to 20 kt. Seas 5 to 7 ft. Wave Detail: East 6 ft at 8 seconds, northeast 3 ft at 5 seconds and north 2 ft at 10 seconds. .FRIDAY...Northeast wind 10 to 15 kt. Seas 4 to 5 ft. Wave Detail: East 3 ft at 8 seconds, north 3 ft at 11 seconds and northeast 2 ft at 4 seconds. $$