Tropical Storm Lionrock formed over the South China Sea southeast of Hainan on Thursday. At 5:00 p.m. EDT on Thursday the center of Tropical Storm Lionrock was located at latitude 17.5°N and longitude 111.0°E which put it about 95 miles (150 km) southeast of Lingshui, China. Lionrock was moving toward the north-northwest at 5 m.p.h. (8 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 994 mb.

The circulation around a low pressure system over the South China Sea strengthened on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Lionrock. There was a broad center of circulation in the middle of Tropical Storm Lionrock. Many of the thunderstorms were occurring in bands northeast and southwest of the broad center. Storms in the bands generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 150 miles (240 km) on the eastern side of Lionrock. Winds to tropical storm force extended out 75 miles (120 km) on the western side of the circulation.

Tropical Storm Lionrock will move through an environment somewhat favorable for intensification during the next 24 hours. Lionrock will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the eastern side of a small upper level ridge. The ridge will produce northeasterly winds that will blow toward the top of Lionrock’s circulation. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. Tropical Storm Lionrock is likely to intensify slowly during the next 24 hours because of the broad center of circulation.

Tropical Storm Lionrock will move around the southwestern part of a subtropical high pressure system over the Western North Pacific Ocean during the next 24 hours. The subtropical high will steer Lionrock toward the north-northwest. On its anticipated track the center of Tropical Storm Lionrock will reach Hainan in 24 hours. Lionrock will bring gusty winds and locally heavy rain to Hainan. Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, a tropical depression formed east of the Philippines. At 5:00 p.m. EDT on Thursday the center of the tropical depression was located at latitude 13.3°N and longitude 129.7°E which put it about 400 miles (645 km) east of Legazpi, Philippines. The tropical depression was moving toward the east-northeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1002 mb.