NWS Advisories in Effect for the Marianas

NWS Advisories in Effect for the Marianas

The National Weather Service (NWS), Guam Weather Forecast Office issued the following advisories for the Marianas:

A short term forecast is in effect for Guam and Guam coastal waters. Through 2 p.m., heavy showers and thunderstorms will move across portions of central and southern Guam and adjacent coastal waters. Areas affected include Hagatna and Agana Heights southward to Piti and Apra Harbor and farther to Umatac and Merizo. Up to an inch and a half of rain is possible with occasional lightning strikes.


If driving, be prepared for heavy rain and brief flooding of roads. If outdoors and see lightning is seen or thunder is heard, find safe shelter. Boaters should look for shelter from heavy rain and possible lightning before the thunderstorms arrive.


A marine weather statement was issued for Guam coastal waters west of Umatac and Merizo. Thunderstorms and frequent lightning are expected west of Umatac, Merizo and Coco’s Island and drifting westward. Mariners can expect gusty winds to around 20 knots, locally higher waves, frequent lightning strikes and heavy downpours.


Boaters are advised to seek safe harbor immediately until the thunderstorms pass. Frequent lightning will occur with the thunderstorms. If caught on open water, stay below deck if possible and keep away from underground metal objects.


A coastal hazard statement remains in effect for Guam, Rota, Tinian, and Saipan through Sunday. Large quantities of box jellyfish are expected through Sunday afternoon for the Marianas beaches and surrounding waters. Swimmers and beach goers are advised to stay alert and report jellyfish sightings to life guards, hotel management, or authorities. Avoid contact with jellyfish.


A thunderstorm warning is in effect for the Guam International Airport Authority is until 3 p.m. Thunderstorms are occurring within 5 nautical miles of the airport.


The Offices of Guam Homeland Security and Civil Defense (GHS/OCD) advise residents and visitors to avoid hazardous seas, until conditions subside. Heed the advice of lifeguards, beach patrol flags, and signs. If lightning is seen or thunder is heard, seek shelter immediately.


Visit the following links for the latest information:



For more information, contact GHS/OCD Public Information Officer Jenna G. Blas at (671) 489-2540 or via email at jenna.g.blas@ghs.guam.gov.




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June 2018 is Typhoon Preparedness Month