The Weather of September 2000

    September 2000 was drier and slightly warmer than usual. The mean relative humidity of 72 per cent was the fourth lowest for September. The total rainfall of 152.6 millimetres was only about half the normal figure of 299.7 millimetres. However, the accumulated rainfall from January to September amounted to 2 395.4 millimetres, 19 per cent above the normal of 2 007.1 millimetres for the same period. The monthly mean temperature of 27.7 degrees was 0.1 degree above normal.

    Having intensified into a severe tropical storm at the end of August, Maria began to head towards the south China coast on the early morning of 1 September. It made landfall near Shanwei at about 5 a.m. and weakened quickly into an area of low pressure. During its passage, winds were strong over Hong Kong and there was heavy rain.

    Rainbands associated with the remnant of Maria continued to bring heavy rain and squally thunderstorms to Hong Kong on 2 September. Two men were struck by lightning but escaped serious injury.

    The rain eased off on 3 September and the weather that afternoon was mainly fine. It remained mainly fine the next couple of days. Temperatures rose to a maximum of 32.2 degrees on 5 September, the highest in the month.

    A weak surge of the northeast monsoon reached the south China coastal areas on 6 September but mainly fine weather continued to prevail.

    Wukong formed as a tropical depression over the northern part of the South China Sea on 5 September. As it moved closer to Hong Kong, local winds strengthened gradually during the evening of 7 September. The weather became mainly cloudy with a few rain patches. Wukong, having by now strengthened into a typhoon, passed to the south of Hong Kong on 8 September and local winds were strong offshore and on high ground. Winds moderated as Wukong moved away in the direction of Hainan Island and weakened the next day.

    Under the influence of northerly winds, the weather turned fine and dry on 10 September. These conditions lasted for the next few days. Temperatures fell to a minimum of 23.9 degrees, the lowest in the month, on 14 September under strong winds and clear skies. The relative humidity fell below 40 per cent on the afternoon of 14 and 15 September. Winds gradually moderated and it remained fine and sunny on 16 September.

    As winds turned light on the morning of 17 September, haze was reported over the western part of the territory. The onset of moderate easterlies in the afternoon caused the haze to disperse but brought cloudier weather. It stayed cloudy with sunny periods the next two days.

    A humid easterly airstream brought a few rain patches to the territory on 20 and 21 September. Temperatures again fell to a minimum of 23.9 degrees in rain on 20 September.

    A ridge of high pressure over southeastern China brought generally fine weather to Hong Kong for the rest of the month.

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

    During the month, one aircraft was diverted due to adverse weather.