System Upgraded to a Tropical Depression; Watches in Effect

System Upgraded to a Tropical Depression; Watches in Effect

System Upgraded to a Tropical Depression; Watches in Effect 

The National Weather Service (NWS), Guam Weather Forecast Office continue to monitor what is now Tropical Depression 20W as it forms north-northeast of Pohnpei.  

NWS has issued a typhoon watch for Alamagan in the far Northern Mariana Islands, meaning typhoon conditions, including destructive winds of 74 mph or more, are possible within 48 hours.

Additionally, a tropical storm watch is in effect for Rota, Tinian, Saipan, Pagan, and Agrihan, meaning tropical storm conditions, including damaging winds of 39 mph or more, are possible within 48 hours, around Monday afternoon.

There are no watches in effect for Guam at this time but this can change. The community is reminded to be ready to take preparedness actions if there is a change in the system’s track, posing more of a threat to the island.

As of 7 p.m. this evening, 20W was located 15.3 degrees north latitude and 160.3 degrees east longitude, about 970 miles east of Saipan and 1,045 miles east of Guam. The system is moving west at 17 mph with maximum sustained winds of 30 mph.

NWS advised model guidance maintains a westward motion to bring the circulation through the Marianas between Saipan and Agrihan Monday night or Tuesday.

The Offices of Guam Homeland Security and Civil Defense (GHS/OCD) will continue to monitor the system closely with guidance from NWS and provide updates as needed. The community is advised to heed any additional advisories in the coming days and be prepared to take action, if needed. 
Stay up to date with the latest advisory information in the coming days:  

·  NWS Website:

·  NWS Facebook:

·  GHS/OCD Website:

·  GHS/OCD Facebook:

For more information, contact GHS/OCD Public Information Officer, Jenna G. Blas at (671) 489-2540 or via email at



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June 2018 is Typhoon Preparedness Month