Tropical Storm Yutu formed southeast of the Marianas on Sunday. At 5:00 p.m. EDT on Sunday the center of Tropical Storm Yutu was located at latitude 8.7°N and longitude 156.4°E which put it about 880 miles (1420 km) east-southeast of Guam. Yutu was moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1002 mb.
A distinct low level center of circulation developed in an area or thunderstorms northeast of Chuuk and the Japan Meteorological Agency designated the system as Tropical Storm Yutu. The circulation around Yutu was organizing quickly. An inner band of showers and thunderstorms was wrapping around the center of circulation. Other bands of showers and thunderstorms were forming and they were starting to revolving around the center. Storms near the center were producing upper level divergence which was pumping mass away from the tropical storm.
Tropical Storm Yutu will be moving through an environment that is very favorable for intensification. Yutu will move over water where the Sea Surface Temperature is near 30°C. It will move through an environment where the upper level winds are weak and there will little vertical wind shear. Tropical Storm Yutu could strengthen into a typhoon within 36 hours and it could rapidly intensify into the equivalent of a major hurricane within three or four days.
Tropical Storm Yutu will move around the western end of a subtropical ridge over the Western North Pacific Ocean during the next few days. The ridge will steer Yutu toward the northwest during the next two or three days. On its anticipated track Yutu will approach the Marianas in about three days. It will likely be a typhoon by that time.