FZMY50 PGUM 191908

CWFGUM



Coastal Waters Forecast for the Mariana Islands

National Weather Service Tiyan GU

508 AM ChST Fri Mar 20 2026



Marianas Waters out to 40 nautical miles



PMZ150-200845-

508 AM ChST Fri Mar 20 2026



.Synopsis for Marianas Waters...

Building northeast to east swell, reinforced by diminishing long-

period north to northeast swells from distant low pressure systems

will continue to produce hazardous seas up to 10 feet over 

Marianas coastal waters through at least this afternoon. Overall,

the long-period swells are gradually subsiding, but the building 

northeast to east swell will keep seas elevated, potentially 

remaining at hazardous levels of 8 to 10 feet over eastern coastal

waters of Tinian and Saipan through the weekend. Moderate to 

fresh winds out of the northeast are expected through early next 

week.



$$



PMZ151>154-200845-

MARIANAS COASTAL WATERS-

508 AM ChST Fri Mar 20 2026



...SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE THIS AFTERNOON...



.TODAY...Northeast wind 15 to 20 kt. Seas 8 to 10 ft. Wave

Detail: Northeast 7 ft at 8 seconds, northeast 6 ft at 13 seconds

and northeast 4 ft at 5 seconds. 

.TONIGHT...Northeast wind 15 to 20 kt. Seas 7 to 9 ft. Wave

Detail: Northeast 6 ft at 8 seconds, northeast 5 ft at 13 

seconds, northeast 4 ft at 6 seconds and northeast 3 ft at 14 

seconds. 

.SATURDAY...Northeast wind 15 to 20 kt. Seas 7 to 9 ft. Wave

Detail: Northeast 6 ft at 8 seconds, north 5 ft at 14 seconds, 

east 4 ft at 6 seconds and northeast 3 ft at 14 seconds. 

.SATURDAY NIGHT...Northeast wind 15 to 20 kt. Seas 7 to 9 ft.

Wave Detail: Northeast 6 ft at 8 seconds, northeast 4 ft at 6 

seconds, north 4 ft at 13 seconds and northeast 3 ft at 14 

seconds. 

.SUNDAY...Northeast wind 20 kt. Seas 7 to 9 ft. Wave Detail:

East 7 ft at 9 seconds, northeast 4 ft at 7 seconds, north 3 ft

at 12 seconds and northeast 3 ft at 13 seconds. 

.MONDAY...Northeast wind 15 to 20 kt. Seas 8 to 10 ft. Wave

Detail: East 9 ft at 9 seconds, northeast 4 ft at 6 seconds and

northeast 3 ft at 12 seconds. A chance of showers. 

.TUESDAY...East wind 10 to 15 kt. Seas 7 to 9 ft. Wave Detail:

East 7 ft at 9 seconds, east 3 ft at 5 seconds, north 4 ft at

12 seconds and northeast 2 ft at 11 seconds. A chance of showers.

 



$$