The Weather of August 2000

    In August 2000, Hong Kong was affected by unsettled weather with heavy rain due to passages of troughs of low pressure and tropical cyclones. The total rainfall of 600.7 millimetres was 53 per cent above normal. The accumulated rainfall from January to August amounted to 2 242.8 millimetres, which was not only 31 per cent above the normal of 1 707.4 millimetres for the same period, but also greater than the annual normal of 2 214.3 millimetres. The monthly mean air temperature of 28.5 degrees was close to normal.

    Tropical Cyclone Warning Signals were hoisted for two tropical cyclones during the month. The Black Rainstorm Warning Signal and the Landslip Warning were issued on 24 August.

    A trough of low pressure lingered over the coastal areas of Guangdong and brought heavy thundery showers to Hong Kong on the first few days of the month. Rain was heaviest on 3 August and more than 180 millimetres of rainfall were recorded in the eastern part of Kowloon. Roads were flooded in Junk Bay and Hung Hom. Villagers in a Sai Kung village were evacuated under the threat of flash floods. A retaining wall in Kwai Chung collapsed and a 13-metre tree fell in Happy Valley. Rainy weather brought cooler conditions, and the minimum temperature of 24.1 degrees recorded on 6 August was the lowest in the month.

    The trough weakened on 7 August and weather turned mainly fine apart from a few isolated showers. The weather for the next couple of days remained generally fine apart from some isolated thunderstorms over the northern part of the New Territories on 8 August.

    With long periods of sunshine, it was very hot on 10 and 11 August. Temperatures rose to a maximum of 33.3 degrees on 11 August, the highest in the month. Apart from isolated thunderstorms on the evening of 12 August, sunny and very hot weather prevailed until 14 August.

    Active southwesterlies brought scattered showers on 15 August and thunderstorms the next morning.

   With a ridge of high pressure over southeastern China, it became fine on 17 August. A few isolated thunderstorms occurred in the northern New Territories on 18 August. The next few days were sunny and very hot.

    Typhoon Bilis swept across Taiwan and adopted a more westerly track on the morning of 23 August. In Hong Kong, winds strengthened gradually and the weather became unsettled with a few squally thunderstorms. Bilis made landfall over the coast of Fujian in the afternoon and weakened into a tropical storm.

    Under the combined influence of the rainbands of the remnant of Bilis and strong southwesterly winds, there were heavy thundery showers during the early hours on 24 August. More than 100 millimetres of rainfall were recorded in most areas and over 300 millimetres in the southern part of Hong Kong Island, necessitating the issuance of the Black Rainstorm Warning Signal. There were 184 reports of flooding and 54 reports of landslip. Traffic was seriously affected as floodwater, along with mud and debris, caused severe damage to roads, mostly on Hong Kong Island. A taxi fell 10 metres down a slope after a 20-metre section of Shek O Road collapsed. Another road in Stanley also subsided. A motor cycle was covered in mud in a landslip in Stanley. A 10-metre by 20-metre reinforcement wall in Queensway collapsed. Seven trees were uprooted in Hong Kong Park and damaged some facilities. More than ten people stranded by floodwater in the New Territories and Pokfulam had to be rescued by firemen. Thundery showers continued the next day.

    A trough of low pressure along the south China coast affected Hong Kong on 26 and 27 August, bringing heavy showers and thunderstorms to Hong Kong. There were altogether 40 reports of flooding.

    Maria formed as a tropical depression over the South China Sea near Dongsha on the late evening of 27 August. It remained almost stationary the next day, bringing a few showers to the territory. As Maria moved away from Hong Kong on 29 August, the weather improved and there were sunny periods. It stayed mainly fine on 30 August apart from isolated thunderstorms in the evening. However, Maria took a northerly track on 31 August and moved towards the coast of Guangdong. Under the influence of its rainband, there were squally showers and thunderstorms in the afternoon.

    Six tropical cyclones occurred in the South China Sea and the western North Pacific in the month.

    During the month, a total of 16 aircraft was diverted due to adverse weather.