Tropical Storm Tembin formed east of the Philippines on Wednesday. At 1:00 p.m. EST on Wednesday the center of Tropical Storm Tembin was located at latitude 9.0°N and longitude 130.7°E which put it about 270 miles (435 km) east of Mindanao. Tembin was moving toward the west at 12 m.p.h. (20 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 1000 mb.
A more well organized center of circulation developed on the eastern edge of a cluster of thunderstorms east of the Philippines and the Japan Meteorological Agency classified the system as Tropical Storm Tembin. The distribution of thunderstorms in Tembin is asymmetrical. Most of the storms are forming in bands north and west of the center of circulation. Those storms are generating upper level divergence which is pumping mass away from the core of Tembin. There are a few thunderstorms in bands on the eastern periphery of the circulation, but most of the bands in the eastern half of Tropical Storm Tembin contain only low clouds and showers.
Tropical Storm Tembin will be moving through an environment favorable for intensification during the next several days. Tembin will move over water where the Sea Surface Temperature is near 29°C. An upper level ridge north of Tembin is producing easterly winds which are blowing toward the top of the circulation. Those winds are causing moderate vertical wind shear and they are probably the reason why most of the thunderstorms are developing west of the center of circulation. However, the shear has not been enough to prevent Tembin from organizing and Tembin is likely to strengthen during the next 24 hours. The center of Tembin will move over Mindanao later on Thursday and it will weaken while the center is over land. Tropical Storm Tembin will likely intensify once the center moves west of Mindanao.
A subtropical ridge north of Tembin is steering the tropical storm toward the west and a general westerly motion is expected to continue for several more days. On its anticipated track the center of Tropical Storm Tembin could approach Mindanao in about 24 hours. Tembin is then forecast to move over the Bohol Sea and Sulu Sea and on toward Palawan. It currently looks like Tropical Storm Tembin will take a track a little to the south of the track taken by Tropical Storm Kai-tak across the Philippines last week.
Tropical Storm Tembin will drop heavy rain over parts of Mindanao, southern Leyte, Bohol, Cebu, Negros, Siargao, and Dinagat. The heavy rain could cause floods and mudslides. The northern part of Tropical Storm Tembin could drop heavy rain in some of the places affected by Tropical Storm Kai-tak last week. Any additional rain in those locations would hamper efforts to recover from floods and mudslides caused by Kai-tak.
Tropical Storm Kai-Tak continue to move southwest over the South China Sea. At 4:00 p.m. EST on Wednesday the center of Tropical Storm Kai-tak was located at latitude 6.4°N and longitude 111.1°E which put it about 440 miles (710 km) southeast of Ho Chi Minh City, Vietnam. Kai-tak was moving toward the southwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 998 mb.