FZMY50 PGUM 200651

CWFGUM



Coastal Waters Forecast for the Mariana Islands

National Weather Service Tiyan GU

451 PM ChST Fri Mar 20 2026



Marianas Waters out to 40 nautical miles



PMZ150-202200-

451 PM 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 seas of 7 to 9 feet over Mariana's 

waters with periods of locally higher seas possible for 

northeastern Tinian and Saipan waters. Seas may build back to 10 

feet or higher as early as Saturday night as the trade swell 

continues to build. Overall, seas are anticipated to hover around

the threshold for Small craft Advisory through the middle of next

week.



$$



PMZ151>154-202200-

MARIANAS COASTAL WATERS-

451 PM ChST Fri Mar 20 2026



...SMALL CRAFT ADVISORY WILL EXPIRE AT 5 PM CHST THIS AFTERNOON...



.TONIGHT...Northeast wind 15 to 20 kt with occasional gusts to 25

kt. Seas 7 to 9 ft. Wave Detail: Northeast 5 ft at 11 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 5 ft at 11 seconds, north 5 ft at 13 seconds,

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

.SATURDAY NIGHT...Northeast wind 20 kt. Seas 8 to 10 ft. Wave

Detail: Northeast 6 ft at 12 seconds, northeast 5 ft at

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

seconds. 

.SUNDAY...Northeast wind 20 kt. Seas 8 to 9 ft. Wave Detail:

Northeast 6 ft at 11 seconds, northeast 5 ft at 7 seconds, north

3 ft at 12 seconds and northeast 3 ft at 13 seconds. 

.SUNDAY NIGHT...Northeast wind 20 kt with occasional gusts to 30 

kt. Seas 7 to 9 ft. Wave Detail: East 7 ft at 9 seconds, northeast

5 ft at 7 seconds and northeast 3 ft at 12 seconds.

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

Detail: East 8 ft at 9 seconds, northeast 5 ft at 6 seconds and 

northeast 3 ft at 12 seconds. 

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

East 7 ft at 9 seconds, northeast 3 ft at 5 seconds, north 3 ft at

10 seconds and northeast 3 ft at 11 seconds. 

.WEDNESDAY...Northeast wind 15 kt. Seas 6 to 8 ft. Wave Detail:

East 6 ft at 8 seconds, northeast 3 ft at 5 seconds, northeast

3 ft at 10 seconds and northeast 2 ft at 10 seconds.  



$$