Former Typhoon Man-yi weakened to a tropical storm over the South China Sea on Monday. At 10:00 a.m. EST on Monday the center of Tropical Storm Man-yi was located at latitude 18.6°N and longitude 115.4°E which put the center about 280 miles (450 km) south-southeast of Hong Kong. Man-yi was moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 993 mb.
Former Typhoon Man-yii weakened to a tropical storm after it hit Luzon on Sunday. An eye was no longer present at the center of Man-yi’s circulation. Bands of showers and thunderstorms were revolving around the center of Tropical Storm Man-yi. Storms near the center of Man-yi still generated some upper level divergence that pumped mass away to the northeast of the tropical storm. The removal of mass was less that the amount of mass converging in the lower levels of Tropical Storm Man-yi. So, the surface pressure was increasing.
The distribution of wind speeds around Tropical Storm Man-yi became more asymmetrical as Man-yi moved over the South China Sea. Winds to tropical storm force extended out 275 miles (445 km) in the northern side of Man-yi’s circulation. The large area of tropical storm force winds on the northern side of Tropical Storm Man-yi was partly due to Man-yi’s interaction with a high pressure system over China. Winds to tropical storm force extended out 150 miles (240 km) in the southern part of Tropical Storm Man-yi.
Tropical Storm Man-yi will move through an environment unfavorable for intensification during the next 24 hours. Man-yi will move over water where where the Sea Surface Temperatures are near 27°C. It will move under the eastern side of an upper level trough over China. The upper level trough will produce southwesterly winds that will blow toward the top of Man-yi’s circulation. Those winds will cause moderate vertical wind shear. In addition, the high pressure system over China will transport colder, drier air toward Tropical Storm Man-yi. The effects of moderate vertical wind shear and colder, drier air will cause Tropical Storm Man-yi to weaken during the next 24 hours.
Tropical Storm Man-yi will move around the southern side of the high pressure system over China. The high pressure system will steer Man-yi toward the west during the next 24 hours. On its anticipated track, Tropical Storm Man-yi will move toward Hainan.