Tropical Storm Cempaka developed over the Western North Pacific Ocean northwest of the Marianas on Friday night. At 4:00 a.m. EST on Saturday the center of Tropical Storm Cempaka was located at latitude 20.3°N and longitude 142.1°E which put the center about 345 miles (555 km) south-southeast of Iwo To. Cempaka was moving toward the northwest at 18 m.p.h. (30 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 999 mb.
A low pressure system over the Western North Pacific Ocean strengthened on Friday night and the Japan Meteorological Agency designated the system as Tropical Storm Cempaka.
More thunderstorms formed near the center of Tropical Storm Cempaka on Friday night. More thunderstorms also developed in the bands revolving around the center of Cempaka’s circulation. Storms near the center of Cempaka generated upper level divergence that pumped mass away from the tropical storm. The removal of mass caused the surface pressure to decrease.
Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Storm Cempaka.
Tropical Storm Cempaka will move through an environment that will be favorable for intensification during the next 24 hours. Cempaka will move over water where the Sea Surface Temperatures are near 28°C. It will move under the southwestern part of an upper level ridge that is over the Western North Pacific Ocean. The upper level ridge will produce southeasterly winds that will blow toward the top of Cempaka’s circulation. Those winds will cause some vertical wind shear. The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification. Tropical Storm Cempaka will intensify during the next 24 hours. Cempaka is likely to strengthen to a typhoon by the end of the weekend.
Tropical Storm Cempaka will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Cempaka toward the northwest during the next 24 hours. On its anticipated track, Tropical Storm Cempaka will move southwest of Iwo To. Cempaka is likely to turn back toward the east-northwest early next week when it reaches the western end of the high pressure system.