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THE ENVIRONMENT
and rapidly dissipated, but its remnants continued to move westwards to central China and activated the south-west monsoon over the South China Sea. As a result, periods of heavy rain and scattered thunderstorms affected Hong Kong from August 19 to 21.
Severe Tropical Storm Cora formed over the South China Sea about 230 miles south-east of Hong Kong on August 25. It moved along a west north-westerly track and passed south of Hong Kong, causing a few hours of fresh winds and some scattered showers. Cora finally dissipated over North Vietnam on August 29.
September was warm and the mean monthly pressure of 1011.3 mb was the highest on record for the month. A cold front moved south and crossed the South China coast on September 24, causing periods of heavy rain and thunderstorms in Hong Kong.
October was much drier than usual and the total rainfall for the month was 63 per cent below normal. Tropical Storm Lorna developed about 330 miles south of Hong Kong at the beginning of the month. It moved rapidly west north-westwards towards Hainan and brought scattered showers to Hong Kong on October 2. During the remainder of the month, three surges of cold air arrived from the north causing cooler conditions in Hong Kong. The Strong Monsoon Signal was hoisted on two occasions and a Yellow Fire Warning was issued on October 21, when the relative humidity dropped below 65 per cent. This was the first warning issued since the introduction of the new Fire Warning System on October 9.
Since records began in 1884, Typhoon Pamela was the sixth tropical cyclone to affect-Hong Kong in November. It formed to the east of the Philippines on No- vember 4 and moved westwards, entering the South China Sea on November 6. It then started to move north-westwards, and after passing over the eastern coast of Hainan, it turned to a north north-easterly course and crossed the South China coast about 180 miles west south-west of Hong Kong on November 8. During the passage of Pamela, gales were experienced in Hong Kong's exposed places for five hours, with the max- imum gust peak speed recorded being 83 knots at Tate's Cairn. Altogether, 73.8 mm of rainfall were recorded at the Royal Observatory between November 8 and 9.
Cloudy conditions with periods of rain persisted through the middle of Novem- ber. A cold front passed through Hong Kong on November 23, and the weather became generally fine with low humidities and long periods of sunshine. Fire danger warnings were issued on six occasions.
December was slightly cloudier than usual. There were several outbreaks of cold dry northerly air during the month, alternating with periods of warm and relatively humid weather. Typhoons Therese and Sally entered the South China Sea at the beginning of the month, but they both moved across the South China Sea on a westerly course and did not affect Hong Kong.
The Royal Observatory
The Royal Observatory is directly concerned with all matters relating to mete- orology, geophysics and environmental sciences. It provides a diversity of services on a broad spectrum of environmental problems. These services not only play an