Thunderstorm advisory in effect; disturbance expected to pass near or through Marianas

A flood advisory is in effect. (PNC file photo)

The National Weather Service (NWS) Guam Weather Forecast Office continues to monitor a developing tropical disturbance north of Chuuk, which is now the subject of a Tropical Cyclone Formation Alert issued by the Joint Typhoon Warning Center, meaning the formation of a tropical cyclone is possible within the next 24 hours.

As of Tuesday night, the circulation was centered north of Chuuk, near 11 degrees north latitude and 152 degrees east longitude, approximately 480 miles east-southeast of Guam, moving west-northwest at 13 mph. The disturbance is expected to strengthen as it heads near or through the Marianas by the end of this week.

A thunderstorm advisory is in effect for Guam International Airport Authority until 12 noon. Thunderstorms are possible or occurring within 20 nautical miles of the airport. Be alert and take precautions as necessary. These storms have been producing occasional lightning. If lightning is seen or thunder is heard, remain indoors.

At this time, uncertainty remains for the exact forecast track and intensity of the system as it approaches the Marianas. Showers, thunderstorms, and gusty winds are still likely today through Friday. Depending on how organized the system is and where it tracks when it approaches, current estimates call for 1 to 3 inches of rainfall, with locally higher amounts possible. Sustained winds of 15 to 25 mph, with gusts to 35 mph are possible in the stronger showers and thunderstorms. Changes to this forecast remain likely.

To prepare for any circumstance, the community is advised to take precautionary measures now through Wednesday evening:

· Stay up to date with the latest information in the coming days. The system track or intensity may change and advisories may be issued.

· Locate or prepare your emergency preparedness kits for your household; stock up on non-perishable food items and water for your household, flashlights, first-aid kits, batteries, matches or lighters, portable stove, toiletries, etc. Visit for more information on what to include in your supplies list.

· Secure important documents such as birth certificates, tax papers, and insurance documents and keep copies in a water-proof bag.

· Clear loose debris around your yard and store any items that may become airborne with heavy winds, before inclement weather arrives.

· Gas your vehicles and get fuel for your generators now while the weather is clear.

· Be prepared to take action if flood advisories are issued. In inclement weather, avoid camping, parking, or hiking along streams, rivers, and creeks during heavy rainfall. These areas can flood quickly and with little warning. Visit to learn more.

The Offices of Guam Homeland Security and Civil Defense (GHS/OCD) remind the community to practice caution while traveling in rainy conditions, driving below the speed limit and allowing enough braking distance between vehicles.

Visit the following links for the latest advisory information:

· NWS Website:

· NWS Facebook:

· GHS/OCD Website:

· GHS/OCD Facebook: