683
FZMY50 PGUM 301855
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
455 AM ChST Fri Jul 31 2026

Marianas Waters out to 40 nautical miles

PMZ150-310845-
455 AM ChST Fri Jul 31 2026

.Synopsis for Marianas Waters...
Light to moderate westerlies for the Marianas coastal waters for
today. Distant Super Typhoon Dolphin is generating a long-period
easterly swell that will reach the Marianas tonight, shifting
northerly by midweek. A monsoon pattern will introduce increasing
southwest to west winds and a building southwesterly swell by the
end of the weekend, which will most likely induce hazardous sea
conditions to small craft vessels.

$$

PMZ151-310845-
Guam Coastal Waters-
455 AM ChST Fri Jul 31 2026

...GALE WATCH IN EFFECT FROM SUNDAY THROUGH TUESDAY...

.TODAY...West wind 5 to 15 kt. Seas 3 to 5 ft. Wave Detail:
Southwest 3 ft at 8 seconds, south 3 ft at 8 seconds and west 2 ft
at 4 seconds.
.TONIGHT...West wind 10 to 15 kt. Seas 4 to 6 ft. Wave Detail:
South 4 ft at 10 seconds, west 3 ft at 4 seconds and southwest 3
ft at 8 seconds. Scattered showers.
.SATURDAY...West wind 10 to 20 kt. Seas 5 to 7 ft. Wave Detail:
Southwest 4 ft at 8 seconds, southeast 4 ft at 14 seconds and west
3 ft at 5 seconds. Scattered showers.
.SATURDAY NIGHT...West wind 15 to 20 kt with gusts to 30 kt. Seas
6 to 8 ft. Wave Detail: West 5 ft at 9 seconds, west 4 ft at 6
seconds and east 4 ft at 14 seconds. Scattered showers.
.SUNDAY THROUGH TUESDAY...Southwest wind 20 to 30 kt with frequent
gusts to 40 kt. Seas 9 to 12 ft. Wave Detail: Southwest 8 ft at 8
seconds, northwest 8 ft at 14 seconds and west 5 ft at 9 seconds.
A chance of showers with a slight chance of thunderstorms.

$$

PMZ152>154-310845-
Rota Coastal Waters-Tinian Coastal Waters-Saipan Coastal Waters-
455 AM ChST Fri Jul 31 2026

.TODAY...Southwest wind 10 kt. Seas around 4 ft. Wave Detail:
Southeast 3 ft at 8 seconds and southwest 3 ft at 8 seconds.
.TONIGHT...Northwest wind 5 to 10 kt. Seas 3 to 5 ft. Wave
Detail: Southwest 3 ft at 8 seconds and southeast 3 ft at
13 seconds.
.SATURDAY...West wind 5 to 15 kt. Seas around 6 ft. Wave Detail:
Southwest 4 ft at 8 seconds, east 4 ft at 14 seconds and west
2 ft at 4 seconds. Scattered showers in the afternoon.
.SATURDAY NIGHT...West wind 10 to 15 kt. Seas 6 to 8 ft. Wave
Detail: West 5 ft at 9 seconds, east 5 ft at 15 seconds and west
2 ft at 4 seconds. Scattered showers.
.SUNDAY...West wind 15 to 20 kt with gusts to 30 kt. Seas 8 to 10
ft. Wave Detail: Northeast 7 ft at 14 seconds, west 5 ft at 9
seconds and west 4 ft at 6 seconds. A chance of showers.
.MONDAY THROUGH TUESDAY...Southwest wind 20 to 25 kt with gusts to
35 kt. Seas 9 to 12 ft. Wave Detail: Northwest 9 ft at 14
seconds, southwest 7 ft at 8 seconds and west 5 ft at 9 seconds. A
chance of showers with a slight chance of thunderstorms.

$$