Tropical Storm Chaba strengthened over the South China Sea south of Hong Kong on Thursday night. At 11:00 p.m. EDT on Thursday the center of Tropical Storm Chaba was located at latitude 18.6°N and longitude 113.7°E which put it about 275 miles (445 km) south of Hong Kong, China. Chaba was moving toward the northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 991 mb.

Tropical Storm Chaba strengthened south of Hong Kong on Thursday night. The inner end of a rainband wrapped around most of the center of circulation. The strongest winds were occurring in the part of the rainband wrapped around the center. Bands of thunderstorms were occurring in the southern half of Chaba’s circulation. Bands in the northern half of Chaba contained more showers and lower clouds. Storms near the center of circulation pumped mass away to the south and west of the tropical storm. Winds to tropical storm force extended out 140 miles (225 km) from the center.

Tropical Storm Chaba will move through an environment favorable for intensification during the 24 hours. Chaba will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the middle of an upper level ridge over the northern part of the South China Sea. The upper level winds are weak near the center of the ridge and there will be little vertical wind shear. Tropical Storm Chaba will continue to intensify during the next 24 hours and it could strengthen to a typhoon.

Tropical Storm Chaba will move around the western end of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high will steer Chaba toward the northwest. On its anticipated track the center of Tropical Storm Chaba could be near the northeastern part of Hainan Island in 18 hours. Chaba could approach the coast of southern China near Zhanjiang in 24 hours. Chaba could be a typhoon when it approaches southern China. It will bring strong winds and locally heavy rain. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Aere formed south-southeast of Okinawa. At 11:00 p.m. EDT on Thursday the center of Tropical Storm Aere was located at latitude 20.8°N and longitude 130.8°E which put it about 470 miles (760 km) south-southeast of Okinawa. Aere was moving toward the east-northeast at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1000 mb. Tropical Storm Aere is forecast to move toward the north-northwest and to strengthen gradually. Aere could be near Okinawa in 36 hours.