TROPICAL CYCLONES IN 2008

3.6	Tropical Storm Higos (0817) : 30 September - 5 October 2008

Higos was the sixth tropical cyclone that necessitated the issuance of a tropical cyclone warning signal in Hong Kong in 2008.

Higos formed as a tropical depression over the western North Pacific about 2,000 km southeast of Hong Kong on the early hours of 30 September and moved northwestwards. It crossed the central part of the Philippines that afternoon and the next day and turned to move west-northwestwards, entering the central part of the South China Sea on the early hours of 2 October. Higos intensified into a tropical storm on the morning of 3 October and moved northwestwards. It turned to move northwards that night and made landfall near Wenchong at the eastern tip of Hainan. It weakened into a tropical depression on the early hours of 4 October and made landfall again near Wuchuan in western Guangdong that night. Higos then turned to move north-northeastwards across the coastal areas of western Guangdong and weakened into an area of low pressure on the early hours of 5 October. Under the influence of westerlies at upper levels, the remnant low pressure area of Higos moved generally eastwards across the coastal areas of western Guangdong that morning and passed close to Zhongshan and Guangzhou in the evening. Under the influence of cooler air spreading southwards over south China, the low pressure area attained characteristics of an extra-tropical cyclone. The low pressure area moved across the coast of Guangdong on 6 October and dissipated over the northern part of the South China Sea on 7 October. According to press reports, over 40 000 boats returned to the ports for shelter in Hainan and Guangdong.

In Hong Kong, the Standby Signal No. 1 was issued at 7.30 p.m. on 2 October when Higos was about 700 km south of Hong Kong. Local winds were moderate east to northeasterlies that day. Winds became locally strong in offshore waters and on high grounds for the following two days. Cheung Chau recorded a maximum 10-minute mean wind speed of 49 km/h, the highest in the eight reference stations in the network of reference anemometers in the tropical cyclone warning system. All tropical cyclone warning signals were cancelled at 10.30 p.m. on 4 October as Higos made landfall over western Guangdong and weakened. At the Hong Kong Observatory Headquarters, the lowest instantaneous mean sea-level pressure of 1007.7 hPa was recorded at 5.00 p.m. and 5.01 p.m. on 4 October, when Higos was about 370 km west-southwest of Hong Kong. The remnant low pressure area of Higos brought strong south to southwesterlies, occasionally reaching gale force, to the offshore waters and high grounds of Hong Kong on the evening of 5 October. The Strong Monsoon Signal was in force between 5.45 p.m. and 11.40 p.m that day.

There were sunny periods and a few showers on 2 October. The weather turned cloudy with rain patches on 3 October and a few heavy showers the next day. The remnant low pressure area of Higos brought heavy squally showers and thunderstorms to Hong Kong on 5 October and the Amber Rainstorm Warning Signal was in force between 8.50 a.m. and 11.30 a.m. and also between 6.15 p.m. to 8.40 p.m. More than 100 millimetres of rainfall were recorded in many parts of the territory that day.

In Hong Kong, a sheet of glass fell off from a shopping centre in Tsim Sha Tsui when the Strong Monsoon Signal was in force. Two vehicles were damaged and a person was slightly injured during the incident. In addition, a scaffolding was reported loose in Kowloon Bay. At the Hong Kong International Airport, 40 flights had to be diverted due to adverse weather on 5 October.

Information on the maximum wind, periods of strong winds, periods of strong winds, daily rainfall and maximum sea level during the passage of Higos is given in Tables 3.6.1 - 3.6.4. Figures 3.6.1 - 3.6.4 show the track of Higos and its remnant low pressure area, rainfall distribution, satellite imageries of Higos and the radar imagery of its remnant low pressure area respectively.

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