The Weather of July 2001

    The weather of July 2001 was wetter and cooler than usual. The monthly rainfall of 656.4 millimetres was more than double the normal figure of 323.5 millimetres and ranked the tenth highest for July. The accumulated rainfall since 1 January amounted to 2 150.0 millimetres, 63 per cent above the normal figure of 1 316.0 millimetres for the same period and ranked the third highest for the period. The mean temperature was 28.1 degrees, 0.7 degrees below normal. Furthermore, the monthly total bright sunshine duration of 136.3 hours was the third lowest for the month. Two tropical cyclones passed close to Hong Kong and necessitated the hoisting of the No. 8 Gale or Storm Signal.

    Over the northern part of the South China Sea, Severe Tropical Storm Durian intensified into a typhoon on 1 July while moving northwest towards Leizhou Peninsula. Strong easterly winds prevailed over Hong Kong and there were occasional gales offshore and on high grounds. The outer rainbands of Durian also brought heavy squally showers and thunderstorms. A waterspout was observed over the Tathong Channel between Shek O and Tung Lung Chau at around 12:50 p.m. The waterspout moved westwards and landed over Rocky Bay in Shek O five minutes later where it dissipated. As Durian made landfall near Zhanjiang on 2 July and started to weaken, local winds moderated.

    Under the influence of a ridge of high pressure, the weather of Hong Kong became fine on 3 July apart from some scattered showers in the morning.

    Typhoon Utor over the western Pacific skirted the northern coast of Luzon and entered the South China Sea on 4 July. The weather of Hong Kong became hazy and very hot, with a maximum temperature of 33.2 degrees, the highest in the month.

    Utor edged further towards the coast of Guangdong on 5 July and brought thundery showers to Hong Kong. It weakened and made landfall near Shanwei on 6 July. After landing, it tracked generally westwards skirting Hong Kong within 100 kilometres to the north. Strong to gale force winds prevailed over the territory in heavy rain and squally thunderstorms. The high winds and low pressure of Utor also brought storm surge to the territory. Coupled with the astronomical high tide occurring in the morning, high sea level resulted in the inundation of some low-lying coastal areas in Tai O, Lau Fau Shan and Sheung Wan. As Utor weakened further and moved away, local winds subsided on 7 July.

    With a ridge of high pressure building over southeastern China, weather became fine on 8 July apart from a few isolated showers. Fine and hot weather persisted the next three days.

    The southwest monsoon affected the south China coastal areas on 12 July and the weather of Hong Kong turned cloudy.

    The rainbands associated with the remnant of Tropical Storm Trami which crossed the Taiwan Strait and dissipated earlier brought heavy thunderstorms to Hong Kong on the early morning of 13 July. The weather improved in the afternoon and became mainly fine the next day.

    An active trough of low pressure along the south China coast brought heavy rain and thunderstorms to Hong Kong on 15 July. There were altogether 13 reports of flooding and Lantau Island was the most affected area. A minor landslip occurred in Lantau Island and a road subsided in Wong Chuk Hang. Temperatures dropped to a minimum of 24.3 degrees in heavy rain, the lowest in the month. The trough lingered near the coast and continued to bring unsettled weather to the territory till 20 July. The weather improved on the afternoon of 20 July and there were sunny periods.

    Another trough of low pressure over the northern part of the South China Sea again brought heavy thundery showers to Hong Kong on 21 July. Showers gradually eased off the next day.

    A ridge of high pressure over southeast China brought fine and hot weather to Hong Kong on 23 July.

    Tropical Storm Yutu over the Luzon Strait entered the South China Sea and intensified rapidly into a typhoon on 24 July. Local winds became strong and there were squally showers and thunderstorms. Winds strengthened quickly to gale force offshore and on high grounds the next morning as Yutu came closer to the coast of Guangdong. Winds began to weaken in the evening as Yutu moved away from the territory but showers and thunderstorms continued till 26 July.

    A ridge of high pressure over southeast China brought sunny periods to Hong Kong on 27 July. Fine and hot weather persisted for the rest of the month.

    There were altogether six tropical cyclones in the South China Sea and the western North Pacific in the month.