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June 2009 was drier than usual with total rainfall of 341.8 millimetres for the month about 12% below the normal figure of 388.1 millimetres.
The accumulated rainfall for 2009 to the end of June was 817.5 millimetres, about 22% below the normal figure of 1054.7 millimetres. The mean temperature was 28.1 degrees, 0.2 degrees above the normal figure of 27.9 degrees.
A ridge of high pressure brought mainly fine weather to Hong Kong on the first day of the month. Under the influence of a southerly airstream over the coastal areas of Guangdong, the weather turned cloudy with isolated showers on June 2. At the same time, a trough of low pressure developed over the northern part of southern China and moved south gradually. It brought heavy rain and squally thunderstorms to the territory on June 3 and 4. More than 70 millimetres of rainfall were recorded over parts of the New Territories on the morning of June 4. With the westward extension of the Pacific ridge, local weather turned fine in the afternoon of June 4. It remained sunny and hot from June 5-7. The temperature at the Hong Kong Observatory rose to a maximum of 32.9 degrees on June 6, the highest of the month.
A humid maritime airstream dominated over the coastal areas of Guangdong and brought cloudy and showery weather to Hong Kong for the ensuing three days. Affected by an active trough of low pressure over southern China, local weather deteriorated further with occasional rain and squally thunderstorms from June 11-16. A ridge of high pressure developed over southern China on June 17, bringing fine and hot weather to Hong Kong on that day.
Affected by the subsidence air mass associated with Severe Tropical Storm Linfa over the northern part of the South China Sea, local weather remained sunny and hot apart from a few isolated showers from June 18-21. After Linfa made landfall over Fujian on the night of June 21, an active southwesterly airstream prevailed over the coastal areas of southern China and brought thundery showers to Hong Kong from June 22-24.
Tropical Storm Nangka entered the South China Sea on the evening of June 24 and edged towards the coast of eastern Guangdong in the next two days. Nangka made landfall over the vicinity of Daya Bay and weakened into an area of low pressure inland Guangdong in the morning of June 27. Locally, it was mainly cloudy with showers on June 25 and 26. Affected by the remnants of Nangka, the weather was cloudy with heavy rain and a few squally thunderstorms on June 27 and 28. The heavy rain eased off and there were sunny periods on June 29. A ridge of high pressure brought mainly fine and hot weather to the territory on June 30.
Two tropical cyclones 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. Monthly meteorological figures and departures from normal of June are tabulated in Table 2.
Ends/Friday, July 3, 2009
Issued at HKT 18:31
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