FZMY50 PGUM 210713

CWFGUM



Coastal Waters Forecast for the Mariana Islands

National Weather Service Tiyan GU

513 PM ChST Sun Jun 21 2026



Marianas Waters out to 40 nautical miles



PMZ150-212245-

513 PM ChST Sun Jun 21 2026



.Synopsis for Marianas Waters...

Light to gentle winds and combined seas of 3 to 4 feet will 

continue through Wednesday, then seas could increase a little. A 

secondary southwest swell from distant Tropical Storm Mekkhala 

will encompass the region starting Monday before shifting to more 

westerly a day or two later. Invest 94W may bring increased 

showers, gusty winds, and thunderstorm potential in a few days.



$$



PMZ151-152-212245-

Guam Coastal Waters-Rota Coastal Waters-

513 PM ChST Sun Jun 21 2026



.TONIGHT...Southeast wind 5 to 10 kt. Seas 3 to 4 ft. Wave 

Detail: East 3 ft at 8 seconds, southeast 2 ft at 4 seconds and 

southeast 2 ft at 10 seconds. 

.MONDAY...Southeast wind 5 kt. Seas 3 to 5 ft. Wave Detail:

East 4 ft at 8 seconds and southwest 2 ft at 10 seconds. 

Scattered showers with isolated thunderstorms in the afternoon.

.MONDAY NIGHT...West wind 5 kt. Seas 3 to 5 ft. Wave Detail:

East 4 ft at 8 seconds and southwest 2 ft at 10 seconds.

.TUESDAY...Northeast wind 5 to 10 kt with gusts up to 15 kt. Seas

4 to 5 ft. Wave Detail: East 4 ft at 8 seconds, northeast 2 ft at

4 seconds and southwest 2 ft at 10 seconds. Scattered showers 

with isolated thunderstorms.

.TUESDAY NIGHT...Northeast wind 5 to 10 kt with gusts up to 15 

kt. Seas 4 to 5 ft. Wave Detail: East 4 ft at 8 seconds, 

northeast 2 ft at 4 seconds and west 2 ft at 10 seconds. 

Scattered showers with isolated thunderstorms. 

.WEDNESDAY AND THURSDAY...East wind 5 to 10 kt. Seas 3 to 5 ft. 

Wave Detail: East 3 ft at 8 seconds, west 3 ft at 10 seconds and 

east 2 ft at 4 seconds. 

.FRIDAY...East wind 10 to 15 kt. Seas 3 to 5 ft. Wave Detail:

East 3 ft at 4 seconds, east 3 ft at 8 seconds and west 3 ft at 

10 seconds. A chance of showers.



$$



PMZ153-154-212245-

Tinian Coastal Waters-Saipan Coastal Waters-

513 PM ChST Sun Jun 21 2026



.TONIGHT...Southeast wind 5 kt. Seas 3 to 4 ft. Wave Detail: East

3 ft at 8 seconds and southeast 2 ft at 10 seconds. 

.MONDAY...Southeast wind 5 kt. Seas 3 to 4 ft. Wave Detail: East

3 ft at 8 seconds and southwest 2 ft at 10 seconds. Scattered 

showers and isolated thunderstorms after midnight. 

.MONDAY NIGHT...East wind 5 to 10 kt. Seas 4 to 5 ft. Wave Detail:

East 4 ft at 8 seconds, east 2 ft at 4 seconds and southwest 2 ft

at 10 seconds. Isolated thunderstorms. Scattered showers after 

midnight.

.TUESDAY...Northeast wind 10 to 15 kt with gusts up to 20 kt. 

Seas 5 to 6 ft. Wave Detail: East 4 ft at 8 seconds, northeast 4 

ft at 4 seconds and southwest 2 ft at 10 seconds. Scattered 

showers with isolated thunderstorms.

.TUESDAY NIGHT...East wind 10 to 15 kt with gusts up to 20 kt. 

Seas 4 to 5 ft. Wave Detail: East 4 ft at 8 seconds, east 3 ft at

4 seconds and west 2 ft at 10 seconds. Scattered showers with 

isolated thunderstorms.

.WEDNESDAY THROUGH THURSDAY...East wind 5 to 15 kt. Seas 3 to

5 ft. Wave Detail: East 4 ft at 8 seconds, east 3 ft at 4 seconds

and west 3 ft at 10 seconds. 

.FRIDAY...East wind 15 kt. Seas 5 to 6 ft. Wave Detail: East 3 ft

at 4 seconds, east 4 ft at 8 seconds and west 3 ft at 10 seconds.

A chance of showers.



$$