Disturbance seen to pass Marianas today as tropical cyclone

The unorganized tropical disturbance 99W is expected to make landfall in the Marianas region later today and will continue to make its way through the Marianas through the end of the week.

The National Weather Service in Guam expects 99W to become a tropical cyclone as it passes through the Marianas today.

“A Tropical Cyclone Formation Alert continues for this system, which means 99W is expected to become a tropical cyclone by Thursday,” NWS stated.

In a news release from the Office of the Governor last night, Gov. Ralph DLG Torres and the CNMI Office of Homeland Security and Emergency Management are advising CNMI residents to take precautionary measures, with 99W expected to pass near or through the CNMI between Thursday night or Friday morning. 

The news release said that 99W could be upgraded to a tropical depression later last night. 

There are currently no tropical storm watches or warning issued by NWS, but a small craft advisory and a Flash Flood Watch is in effect from this morning through Friday afternoon as heavy rainfall of 3 to 5 inches is expected for Saipan, Tinian, and Rota. Sustained winds of 25 mph with gusts up to 35-40 mph are possible within the CNMI. 

As of 6pm yesterday, the system was still in its formative stage with an elongated circulation center so forecast adjustments are likely to be refined today. “There remains some uncertainty in regards to how fast the disturbance will organize, how strong it’ll be, and the track of the system. That said, at least periods of heavy showers and thunderstorms are likely,” NWS stated in its most recent forecast.

The loosely centered system was last seen about 280 miles east-southeast of the Marianas and was moving in the west-northwest direction, likely passing near or through the Marianas today into Friday.

The Marianas—to include the CNMI and Guam—should expect hazardous marine conditions to intensify throughout the day with east winds between 15 and 25 knots and building, choppy seas.

The tropical disturbance will bring gusty winds and the threat of heavy rain to the islands tomorrow through the end of the week.

Due to the threat posed by 99W, a Flash Flood Watch for a portion of the Marianas, including Rota, Guam, Tinian, and Saipan, will be in effect for the remainder of the week. Heavy showers and thunderstorms associated with the tropical disturbance will affect the islands the next 36 to 48 hours.

From today through Friday afternoon, heavy showers and thunderstorms associated with the tropical disturbance will affect the islands.

Rainfall of 3 to 5 inches with locally heavier amounts are possible for Tinian and Saipan, with two to four inches possible for Rota, and one to three inches for Guam.

In preparation for the tropical disturbance, CNMI residents are urged to take the following precautionary measures through Friday:

• Avoid driving on flooded roads or areas. 

• Secure loose debris and belongings around your household or yard. 

• Have a prepared emergency preparedness kit with first-aid kits, batteries, flashlights, toiletries, and a portable stove in your household. 

• Stock up on food and water for your household. 

• Stay up to date with the latest information from the National Weather Service and the CNMI Office of Homeland Security and Emergency Management. 

CNMI residents are advised to stay safe while traveling in rainy conditions and to be courteous of other drivers out on the road. 

This is an evolving situation. HSEM and the Office of the Governor will continue to provide updates. 

For more information, visit the following: 

• CNMI EOC State Warning Point Facebook: https://www.facebook.com/cnmieocswp/

• CNMI Office of the Governor Facebook: https://www.facebook.com/GovernorCNMI

• Governor Ralph DLG. Torres Facebook: https://www.facebook.com/ralphdlg.torres/

• NWS Website: https://www.weather.gov/gum/

• NWS Facebook: https://www.facebook.com/NWSGuam/