FZMY50 PGUM 120704

CWFGUM



Coastal Waters Forecast for the Mariana Islands

National Weather Service Tiyan GU

504 PM ChST Fri Dec 12 2025



Marianas Waters out to 40 nautical miles



PMZ150-122100-

504 PM ChST Fri Dec 12 2025



.Synopsis for Marianas Waters...

Moderate to fresh trade winds are expected through Wednesday. A 

shear line is slowly moving south through the CNMI and is expected

to move over or just north of Saipan by Saturday. This is 

expected to elevate the winds near Saipan and Tinian to fresh to 

strong. Overall, combined seas of 6 to 7 feet are expected to 

increase by a foot or two for Guam and Rota and seas near Tinian 

and Saipan could rise to near 10 feet over the weekend and may 

warrant a Small Craft Advisory. Around the middle of next week 

another north swell pulse may push through the region.



$$



PMZ151-152-122100-

Guam Coastal Waters-Rota Coastal Waters-

504 PM ChST Fri Dec 12 2025





.TONIGHT...Northeast wind 15 kt. Seas 6 to 7 ft. Wave Detail: 

Northeast 5 ft at 10 seconds, north 3 ft at 10 seconds and east 3 

ft at 5 seconds.

.SATURDAY...East wind 15 kt. Seas 6 to 7 ft. Wave Detail:

Northeast 5 ft at 9 seconds, north 3 ft at 10 seconds and east 3 

ft at 5 seconds. 

.SATURDAY NIGHT...East wind 15 to 20 kt. Seas 6 to 8 ft. Wave

Detail: East 6 ft at 8 seconds, east 4 ft at 5 seconds and 

northeast 3 ft at 9 seconds. 

.SUNDAY...East wind 20 kt. Seas 6 to 8 ft. Wave Detail: Northeast

7 ft at 9 seconds and east 4 ft at 5 seconds. 

.SUNDAY NIGHT...East wind 15 to 20 kt. Seas 7 to 8 ft. Wave

Detail: Northeast 7 ft at 9 seconds and east 4 ft at 6 seconds. 

.MONDAY AND TUESDAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave

Detail: Northeast 7 ft at 9 seconds, east 4 ft at 6 seconds and 

north 3 ft at 11 seconds. 

.WEDNESDAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail:

Northeast 7 ft at 10 seconds, east 4 ft at 6 seconds and north 3 

ft at 11 seconds. 



$$



PMZ153-154-122100-

Tinian Coastal Waters-Saipan Coastal Waters-

504 PM ChST Fri Dec 12 2025



...WINDS AND SEAS ARE EXPECTED TO APPROACH HAZARDOUS LEVELS OVER 

THE WEEKEND... 



.TONIGHT...East wind 15 to 20 kt. Seas 6 to 8 ft. Wave Detail:

Northeast 6 ft at 10 seconds, north 3 ft at 10 seconds and east 4

ft at 5 seconds. 

.SATURDAY...East wind 15 to 20 kt. Seas 6 to 8 ft. Wave Detail:

Northeast 6 ft at 9 seconds, north 3 ft at 10 seconds and east 4 

ft at 6 seconds. 

.SATURDAY NIGHT...East wind 20 to 25 kt. Seas 7 to 9 ft. Wave

Detail: East 7 ft at 8 seconds, east 5 ft at 5 seconds and 

northeast 3 ft at 8 seconds. 

.SUNDAY...East wind 20 to 25 kt. Seas 7 to 9 ft. Wave Detail: 

Northeast 8 ft at 9 seconds and east 5 ft at 7 seconds. 

.SUNDAY NIGHT...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave

Detail: Northeast 8 ft at 9 seconds and east 4 ft at 6 seconds. 

.MONDAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail: 

Northeast 8 ft at 9 seconds, east 4 ft at 5 seconds and north 2 ft

at 11 seconds. 

.TUESDAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail:

Northeast 7 ft at 9 seconds, east 4 ft at 6 seconds and north

3 ft at 11 seconds. 

.WEDNESDAY...East wind 15 to 20 kt. Seas 7 to 9 ft. Wave Detail:

Northeast 7 ft at 10 seconds, east 4 ft at 6 seconds and north 3 

ft at 11 seconds. 



$$