Tropical Depression Twenty-W formed southeast of Guam on Wednesday. At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Twenty-W was located at latitude 11.5°N and longitude 148.1°E which put it about 305 miles (490 km) east-southeast of Guam. The tropical depression moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). T he minimum surface pressure was 1005 mb.

Tropical Depression Twenty-W developed over the Western North Pacific Ocean southeast of Guam on Wednesday. The circulation around the tropical depression was organizing quickly. Thunderstorms formed near the center of the tropical depression. Other thunderstorms developed in bands revolving around the center of circulation. Storms near the center began to generate upper level divergence that pumped mass away from the depression.

Tropical Depression Twenty-W will move through an environment favorable for intensification during the next few days. The tropical depression will move over water where the Sea Surface Temperatures are near 30˚C. It will move into a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Depression Twenty-W could strengthen to a tropical storm during the next 12 hours. It could intensify more rapidly after an inner core becomes more well developed. It could intensify to a typhoon within 36 hours.

Tropical Depression Twenty-W will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next several days. The high will steer the tropical depression toward the northwest during the next 36 hours. On its anticipated track the tropical depression could reach the Marianas in less than 24 hours. Tropical Depression Twenty-W could intensify to a tropical storm before it reaches the Marianas. It will bring gusty winds and locally heavy rain to the Marianas including Guam.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Twentyone-W formed over the South China Sea east of Vietnam. At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Twentyone-W was located at latitude 12.9°N and longitude 112.8°E which put it about 400 miles (605 km) east-southeast of Da Nang, Vietnam. The tropical depression moving toward the west-northwest at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). T he minimum surface pressure was 1005 mb. Tropical Depression Twentyone-W is forecast to move toward the west-northwest and to strengthen to a tropical storm. It could reach the coast of Vietnam south of Da Nang in about 24 hours.