504
FZMY50 PGUM 161800
CWFGUM

Coastal Waters Forecast for the Mariana Islands
National Weather Service Tiyan GU
400 AM ChST Thu Jul 17 2025

Marianas Waters out to 40 nautical miles

PMZ150-171145-
400 AM ChST Thu Jul 17 2025

.Synopsis for Marianas Waters...Gentle to moderate east to
southeast winds will continue across the region through the
weekend. The west-southwest swell has been slower to build, so
seas of 4 to 6 feet are expected to continue. If the swell comes
in a bit higher than projected over the weekend, seas could rise
to 5 to 7 foot. The TUTT is now passing through the Marianas, and
the instability associated with it could help to generate
isolated thunderstorms across the coastal waters today. Increasing
moisture and passing troughs will promote periods of scattered
showers and isolated thunderstorms across the waters beginning
tonight and continuing through the weekend.

$$

PMZ151>154-171145-
MARIANAS COASTAL WATERS-
400 AM ChST Thu Jul 17 2025

.TODAY...East wind 10 to 15 kt. Seas 4 to 6 ft. Wave Detail: East
5 ft at 9 seconds, east 3 ft at 4 seconds and west-southwest 2 ft
at 7 seconds. Isolated thunderstorms.
.TONIGHT THROUGH FRIDAY NIGHT...East wind 10 to 15 kt. Seas 4 to
6 ft. Wave Detail: East 5 ft at 9 seconds, east 3 ft at 4 seconds
and west-southwest 2 ft at 7 seconds. Scattered showers with
isolated thunderstorms.
.SATURDAY...Southeast wind 5 to 15 kt. Seas 4 to 6 ft. Wave
Detail: East 5 ft at 9 seconds, east 3 ft at 4 seconds and west-
southwest 2 ft at 9 seconds. Scattered showers with isolated
thunderstorms.
.SUNDAY...Southeast wind 5 to 10 kt. Seas 4 to 6 ft. Wave Detail:
East 5 ft at 9 seconds, west 3 ft at 9 seconds and southeast 2 ft
at 4 seconds. A chance of showers with a slight chance of
thunderstorms.
.MONDAY...Southeast wind 10 kt. Seas 4 to 6 ft. Wave Detail:
East 4 ft at 9 seconds, west 4 ft at 9 seconds and east 2 ft at 4
seconds. A chance of showers with a slight chance of
thunderstorms.

$$