Tropical Depression 20W formed east-southeast of Guam; officials urge community to prepare

Graphic courtesy National Weather Service, Guam office 

The tropical disturbance that officials have been keeping an eye on for the last few days has developed into a depression. 

Tropical Depression 20W formed east-southeast of Guam, according to the National Weather Service Guam Weather Forecast Office. The system was formerly known as Invest Area 99W. 

As of 1 a.m., 20W was located 11.5 degrees north latitude and 148.1 degrees east longitude, about 375 miles northwest of Chuuk, 260 miles east-southeast of Guam, 295 miles east-southeast of Saipan.

It is moving west-northwest at 10 mph, with maximum sustained winds of 30 mph. 20W is expected to intensify through Saturday, possibly becoming a tropical storm by tonight.

Officials, on Wednesday, said conditions are expected to deteriorate today as the system draws closer and brings rain and rains of up to 25 mph with gusts to 30 mph tonight into tomorrow morning. 

There's a flood watch, small craft advisory, and rip tide warnings in effect for Guam, Rota, Tinian and Saipan. 

While changes to this forecast are still possible, the community is reminded to prepare for any circumstance by taking the following precautionary measures now:

· Those living in areas prone to flooding should be prepared to take action; clear drainage areas and unblock clogged storm drains in your area to minimize the chance of flooding.

· Stay up to date with the latest information. 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 following NWS advisories remain in effect:

A flash flood watch is in effect for Guam, Rota, Tinian, and Saipan, from this morning through Friday afternoon. Heavy showers and thunderstorms associated with the tropical depression are expected.

A high risk of rip currents is in effect for Guam, Rota, Tinian, and Saipan from this morning through Friday afternoon. Dangerous rip currents are expected along east facing reefs of the Marianas. Inexperienced swimmers should remain out of the water due to dangerous surf conditions. Rip currents can sweep even the best swimmers away from shore into deeper water. If caught in a rip current, do not swim against the current. Swim in a direction following the shoreline, then head for the beach when out of the current.

A small craft advisory will be in effect for the coastal waters of Guam, Rota, Tinian, and Saipan from 6 a.m. Thursday to midnight Thursday. East winds of 15 to 25 knots with gusts up to 30 knots and seas of 6 to 9 feet are expected. Conditions will be hazardous to small craft. Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in hazardous conditions.


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