Typhoon Nesat passed south of Hong Kong as it moved across the South China Sea on Monday night. At 11:00 p.m. EDT on Monday the center of Typhoon Nesat was located at latitude 18.0°N and longitude 113.3°E which put it about 285 miles (460 km) south of Hong Kong. Nesat was moving toward the west-southwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h). The minimum surface pressure was 971 mb.

Typhoon Nesat started to weaken on Monday night as it passed south of Hong Kong. A circular eye was still present at the center of Nesat’s circulation. However a break occurred in the southeastern part of the ring of thunderstorms surrounded the eye of Typhoon Nesat. The strongest winds were occurring in the broken ring of thunderstorms. Bands of showers and thunderstorms were occurring in the western half of Nesat. Bands in the eastern side of the circulation consisted primarily of showers and lower clouds. Storms near the center of Nesat generated upper level divergence that pumped mass away to the west of the typhoon.

The circulation around Typhoon Nesat interacted with a large surface high pressure system over southern China to produce a large area of tropical storm force winds in the northern part of Nesat’s circulation. Winds to tropical storm force extended out 400 miles (640 km) in the northern side of Typhoon Nesat. Winds to tropical storm force extended out 120 miles (195 km) in the southern side of Nesat. Winds to typhoon force extended out 40 miles (65 km) from the center of circulation.

Typhoon Nesat will move through an environment unfavorable for intensification during the next 48 hours. Nesat will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the southern part of an upper level ridge that extends over the Western North Pacific Ocean to southern China. The ridge will produce easterly winds that will cause moderate vertical wind shear and the wind shear will inhibit intensification. The surface high pressure system over southern China will produce northeasterly winds that will transport drier air into the northern and western parts of Typhoon Nesat. The vertical wind shear and the drier air will cause Typhoon Nesat to weaken during the next 48 hours.

The surface high pressure system over southern China will steer Typhoon Nesat toward the west during the next 48 hours. On its anticipated track, Typhoon Nesat will pass south of Hainan in 36 hours. Nesat is likely to weaken to a tropical storm by the time it passes south of Hainan. Nesat could bring gusty winds and locally heavy rain to Hainan on Tuesday night and Wednesday.