FZMY50 PGUM 230651
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
451 PM ChST Sun Aug 23 2026

Marianas Waters out to 40 nautical miles

PMZ150-232145-
451 PM ChST Sun Aug 23 2026

.Synopsis for Marianas Waters...
Tropical Depression 19W is well northwest of Yap and will 
contribute a pulse of elevated, long-period southwest swell to 
the Marianas overnight. Gentle to moderate southwest winds 
accompanied by strong, convective gusts will persist through 
Monday. Combined seas of 7 to 9 ft will increase to 8 to 10 ft 
Monday morning, so the previously issued Small Craft Advisory was 
extended, keeping in mind the brief drop in sea heights tonight. 
Scattered showers will become numerous heavy tonight, with 
isolated thunderstorms possible throughout.

$$

PMZ151>154-232145-
MARIANAS COASTAL WATERS-
451 PM ChST Sun Aug 23 2026

...SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH MONDAY 
AFTERNOON...

.TONIGHT...Southwest wind 10 to 15 kt with gusts to 25 kt near
heavier showers. Seas 7 to 9 ft. Wave Detail: Southwest 7 ft at 9
seconds, north 4 ft at 10 seconds, southwest 4 ft at 4 seconds 
and southeast 3 ft at 8 seconds. Numerous heavy showers with 
isolated thunderstorms. 
.MONDAY...Southwest wind 10 to 15 kt with gusts to 25 kt near
heavier showers. Seas 8 to 10 ft. Wave Detail: Southwest 8 ft at 
10 seconds, southwest 4 ft at 4 seconds, southeast 3 ft at 8 
seconds and north 4 ft at 10 seconds. Numerous heavy showers with 
isolated thunderstorms. 
.MONDAY NIGHT...Southwest wind 10 to 15 kt with gusts to 25 kt
near heavier showers. Seas 8 to 10 ft. Wave Detail: Southwest 8 
ft at 10 seconds, north 4 ft at 10 seconds, southwest 4 ft at 4 
seconds and east 2 ft at 12 seconds. Scattered heavy showers with 
isolated thunderstorms. 
.TUESDAY...Southwest wind 5 to 10 kt. Seas 7 to 9 ft. Wave 
Detail: Southwest 7 ft at 10 seconds, northwest 3 ft at 10 
seconds, east 3 ft at 12 seconds and southwest 2 ft at 4 seconds. 
Scattered heavy showers with isolated thunderstorms. 
.TUESDAY NIGHT...Southwest wind 5 to 10 kt. Seas 5 to 7 ft. Wave
Detail: Southwest 6 ft at 9 seconds, east 3 ft at 12 seconds, 
southwest 2 ft at 4 seconds and northwest 2 ft at 10 seconds. 
Scattered heavy showers with isolated thunderstorms. 
.WEDNESDAY...Southwest wind 5 to 10 kt. Seas 4 to 6 ft. Wave
Detail: Southwest 5 ft at 10 seconds, east 3 ft at 12 seconds, 
southwest 2 ft at 4 seconds and northwest 2 ft at 10 seconds. A 
chance of showers with a slight chance of thunderstorms. 
.THURSDAY AND FRIDAY...West wind 5 to 15 kt. Seas 4 to 6 ft.
Wave Detail: West 4 ft at 10 seconds, west 3 ft at 4 seconds and 
northeast 3 ft at 12 seconds. Showers likely with a slight chance 
of thunderstorms.

$$