FZMY50 PGUM 240613
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
413 PM ChST Mon Aug 24 2026

Marianas Waters out to 40 nautical miles

PMZ150-242100-
413 PM ChST Mon Aug 24 2026

.Synopsis for Marianas Waters...
Significant southwesterly swell driven by the monsoon pattern and
Tropical Depression Atsani (19W), well north-northwest of Yap and
west- northwest of the Marianas, along with strong, convectively-
driven gust will give way to choppy seas of 7 to 10 feet through 
tonight. Combined seas are expected to gradually subside to around
5 feet midweek, then gradually rise back up going into the 
weekend. Light to gentle winds tonight are becoming light to 
moderate Tuesday. An unsettled, but disorganized monsoon pattern 
continues to bring scattered showers and isolated thunderstorms 
across the Marianas this week with locally heavy showers possible 
beginning Friday.

$$

PMZ151>154-242100-
MARIANAS COASTAL WATERS-
413 PM ChST Mon Aug 24 2026

...SMALL CRAFT ADVISORY IN EFFECT THROUGH EARLY TUESDAY MORNING...

.TONIGHT...Southwest wind 5 to 10 kt. Seas 7 to 10 ft. Wave 
Detail: Southwest 8 ft at 9 seconds, southwest 3 ft at 4 seconds, 
southeast 3 ft at 8 seconds and north 3 ft at 10 seconds. Isolated
showers becoming scattered showers with isolated thunderstorms.
.TUESDAY...Southwest wind 5 to 15 kt. Seas 6 to 8 ft. Wave 
Detail: West 6 ft at 9 seconds, southwest 3 ft at 4 seconds, 
northwest 2 ft at 10 seconds and east 2 ft at 13 seconds. 
Scattered showers with isolated thunderstorms. 
.TUESDAY NIGHT...West wind 5 to 10 kt. Seas 5 to 6 ft. Wave 
Detail: West 5 ft at 9 seconds, northwest 2 ft at 10 seconds, west
2 ft at 4 seconds, and east 2 ft at 12 seconds. Scattered showers
with isolated thunderstorms. 
.WEDNESDAY...West wind 5 kt. Seas 4 to 5 ft. Wave Detail: West 4 
ft at 8 seconds, northwest 2 ft at 10 seconds and east 2 ft at 11 
seconds. Scattered showers with isolated thunderstorms. 
.WEDNESDAY NIGHT...Southwest wind 5 kt. Seas 4 to 5 ft. Wave 
Detail: West 4 ft at 8 seconds, east 2 ft at 10 seconds and 
northwest 2 ft at 11 seconds. Scattered showers with isolated 
thunderstorms. 
.THURSDAY AND FRIDAY...West wind 5 to 15 kt. Seas 5 to 7 ft.
Wave Detail: West 6 ft at 8 seconds, northwest 3 ft at
11 seconds, southwest 3 ft at 4 seconds and east 2 ft at
10 seconds. A chance of showers with a slight chance of
thunderstorms. Locally heavy showers possible.
.SATURDAY...West wind 10 to 15 kt. Seas 6 to 8 ft. Wave Detail:
West 7 ft at 9 seconds, west 3 ft at 4 seconds and northeast 2 ft
at 12 seconds. A chance of showers with a slight chance of
thunderstorms.  

$$