Tropical Storm Cempaka formed southwest of Hong Kong on Sunday evening. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Cempaka was located at latitude 21.0°N and longitude 113.0°E which put it about 120 miles (195 km) southwest of Hong Kong. Cempaka was moving toward the west-northwest at 3 m.p.h. (5 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 991 mb.

The circulation around a small low pressure system organized quickly on Sunday evening and the Japan Meteorological Agency designated the system as Tropical Storm Cempaka. The inner end of a rainband wrapped most of the way around the center of Cempaka and an eye appeared to be forming in the middle of the tropical storm. Bands of showers and thunderstorms were revolving around the center of Tropical Storm Cempaka. Storm near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 40 miles from the center of Cempaka.

Tropical Storm Cempaka will move through an environment favorable for intensification during the next 24 hours. Cempaka will move over water where the Sea Surface Temperatures are near 30°C during the next 24 hours. It will move under an upper level ridge over the South China Sea. The winds are weak in the ridge and there will be little vertical wind shear. Tropical Storm Cempaka will intensify during the next 24 hours and there is a chance it could strengthen to a typhoon.

Tropical Storm Cempaka will move south of a surface high pressure system over eastern China. The high pressure system will steer Cempaka slowly toward the west-northwest during the next 36 hours. On its anticipated track Tropical Storm Cempaka could approach the south coast of China near Yangjiang in about 24 hours. Cempaka could be a typhoon when it approaches the coast. It will bring gusty winds and heavy rain to the coast of Guangdong province. Cempaka could also produce of storm surge of up to 7 feet (2 meters) along parts of the coast where the wind blows the water toward the shore.

Elsewhere over the Western North Pacific Ocean, Tropical Storm In-Fa strengthened southeast of Okinawa. At 11:00 p.m. EDT on Sunday the center of Tropical Storm In-Fa was located at latitude 24.1°N and longitude 131.3°E which put it about 290 miles (465 km) southeast of Okinawa. In-Fa was moving toward the north-northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 986 mb. Tropical Storm In-Fa is forecast to move toward the west during the next several days and to intensify to a typhoon. In-Fa could be south of Okinawa in 36 hours. It could be over the southwestern Ryukyu Islands in three days and near northern Taiwan in four days.