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May, 2006, was wetter than usual with the monthly rainfall of 431.5 millimetres being about 36% above the normal figure of 316.7 millimetres. The accumulated rainfall since the beginning of the year was 733.1 millimetres which was about 19% above the normal figure of 616.5 millimetres. The rainy weather also meant it was also less sunny in the month. The total bright sunshine duration of 122.2 hours was 31.6 hours below normal.
It was mainly fine and hot on the first day of May. The weather deteriorated with heavy showers and thunderstorms on the next two days as Hong Kong came under the influence of a trough of low pressure over the south China coast. It remained cloudy with a few showers on May 4 and 5.
With the trough of low pressure dissipating, the weather improved and there were some sunny periods on May 6. It was mainly fine and hot in the following six days. The temperature rose to 31.5 degrees on May 8, the highest so far in this year.
A cold front passed Hong Kong on May 13. The temperature fell to a minimum of 20.5 degrees in the early morning of May 14. The weather was mainly fine and dry in the following day. Meanwhile, Severe Tropical Storm Chanchu entered the South China Sea and intensified into a Typhoon. Chanchu moved north steadily towards the south China coast on May 15 and 16. With the approach of Chanchu, the Hong Kong Observatory issued the Standby Signal No 1 on May 15 and then the Strong Wind Signal No 3 on May 17, the first time this year. Locally, the weather became cloudy with scattered showers on May 16 and 17. Winds also strengthened and occasionally reached gale force over offshore and on high ground on May 17. Soon after Chanchu made landfall to the east of Shantou on the early morning of May 18, local weather turned fine and remained so the next day.
The weather became cloudy again on May 20 as a trough of low pressure approached the south China coast from the northern part of the South China Sea. It was rainy with a few squally thunderstorms on the ensuing three days. The weather stayed cloudy with a few showers on May 24.
The clouds dispersed and there were sunny periods on May 25. With the approach of a trough of low pressure from the north, the weather deteriorated gradually on May 26 and 27. The trough of low pressure brought rainy weather to the territory on the last four days of the month.
Only one tropical cyclone occurred in the western North Pacific and the South China Sea in the month.
Details of the issuance and cancellation of various warnings/signals in the month are summarised in Table 1.1. Monthly meteorological figures and departures from normal of May are shown in Table 1.2.
Ends/Friday, June 2, 2006
Issued at HKT 17:18
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