Coastal Waters Forecast
Issued by NWS Tiyan, Guam

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FZMY50 PGUM 171853
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
453 AM ChST Sat Oct 18 2025

Marianas Waters out to 40 nautical miles

PMZ150-180900-
453 AM ChST Sat Oct 18 2025

.Synopsis for Marianas Waters...
Moderate to fresh trade winds are expected through Sunday, tapering
down thereafter as the pressure gradient between the tropics and
mid-latitudes decreases. Combined seas of 6 to 8 feet will stay
elevated and choppy through at least the weekend, as northerly
swells and trade swell continue to mix in, before tapering down by
the middle of next week.

$$

PMZ151>154-180900-
MARIANAS COASTAL WATERS-
453 AM ChST Sat Oct 18 2025

.TODAY...East wind 15 kt with gusts to 25 kt. Seas 5 to 7 ft.
Wave Detail: East 5 ft at 9 seconds, east 3 ft at 5 seconds and
north 3 ft at 12 seconds. Scattered showers.
.TONIGHT...East wind 15 to 20 kt. Seas 6 to 8 ft. Wave Detail:
East 5 ft at 9 seconds, east 4 ft at 6 seconds and north 3 ft at
11 seconds.
.SUNDAY...East wind 15 to 20 kt. Seas 5 to 7 ft. Wave Detail:
East 6 ft at 8 seconds, east 3 ft at 5 seconds and north 3 ft at
10 seconds.
.SUNDAY NIGHT...East wind 10 to 15 kt. Seas 5 to 7 ft. Wave
Detail: East 5 ft at 8 seconds, east 3 ft at 5 seconds and north
2 ft at 10 seconds. Scattered showers.
.MONDAY...East wind 10 to 15 kt. Seas 5 to 7 ft. Wave Detail:
East 5 ft at 8 seconds, north 4 ft at 13 seconds and east 2 ft at
4 seconds. A chance of showers.
.TUESDAY...Southeast wind 10 to 15 kt. Seas 6 to 8 ft. Wave
Detail: East 5 ft at 9 seconds, north 4 ft at 13 seconds and
southeast 2 ft at 4 seconds. A chance of showers.
.WEDNESDAY...Southeast wind 10 kt. Seas 5 to 7 ft. Wave Detail:
East 5 ft at 9 seconds, north 3 ft at 12 seconds and southeast 2
ft at 4 seconds. A chance of showers.

$$