Report on Tropical Depression (3 to 4 August)

A tropical depression formed over the northeastern part of the South China Sea on the night of 3 August and it was the second tropical cyclone affecting Hong Kong this year.

The tropical depression formed over the northeastern part of the South China Sea about 310 km east-southeast of Hong Kong. It tracked west-northwestwards towards the east of the Pearl River Estuary with an estimated maximum sustained wind of 45 km/h near its centre. The tropical depression made landfall over the coast of Huidong on the morning of 4 August and degenerated into an area of low pressure over inland Guangdong after noon.

The Observatory issued the Standby Signal No. 1 at 10:10 p.m. on 3 August when the tropical depression was about 250 km east-southeast of Hong Kong. As the circulation of the tropical depression was relatively loose, local winds were only generally light to moderate north to northwesterlies on the morning of 4 August. The tropical depression came closest to Hong Kong at around 11 a.m. on that day when it was about 80 km northeast of the Observatory Headquarters. With the tropical depression degenerating into an area of low pressure over inland Guangdong, all tropical cyclone warning signals were cancelled at 2:40 p.m. on 4 August.

Under the influence of the rainbands of the tropical depression and its remnant low pressure area, there were occasional heavy showers and squally thunderstorms in Hong Kong on 3 - 5 August. The rain was heaviest on 5 August and the Observatory issued the Amber Rainstorm Warning twice on that day. More than 100 millimetres of rainfall were generally recorded over Hong Kong during 3 - 5 August, rainfall even exceeded 200 millimetres over the eastern part of the territory.

The tropical depression did not cause any significant damage in Hong Kong during its passage. At the Observatory Headquarters, the lowest instantaneous mean sea-level pressure of 1003.6 hPa was recorded at 4:15 a.m. on 4 August. A maximum sea level (above chart datum) of 2.21 m and a maximum storm surge of 0.23 m (above astronomical tide) were recorded at Tsim Bei Tsui and Tai Po Kau respectively.