907
FZMY50 PGUM 180427 AAA
CWFGUM

Coastal Waters Forecast for the Mariana Islands...UPDATED
National Weather Service Tiyan GU
227 PM ChST Sat Oct 18 2025

Marianas Waters out to 40 nautical miles

PMZ150-180800-
227 PM ChST Sat Oct 18 2025

.Update...
Lines of showers and thunderstorms have developed considerably in
the afternoon hours, allowing frequent lightning to form in
eastern Guam waters.

.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>154-180800-
MARIANAS COASTAL WATERS-
227 PM ChST Sat Oct 18 2025

Updated for worsening conditions the rest of today and tonight.

.THIS AFTERNOON...East wind 15 to 20 kt with occasional gusts to
30 kt near heavier showers. Seas 5 to 8 ft. Wave Detail: East 5
ft at 9 seconds, east 4 ft at 5 seconds and north 3 ft at 12
seconds. Numerous heavy showers and isolated thunderstorms.
.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.

$$