Attachments
TROPICAL CYCLONE SUMMARIES FOR 1978
In 1978 thirty-three* tropical cyclones former over the western North Pacific and the South China Sea and thirteen of them attained typhoon intensity. Five tropical cyclones crossed the coast of China while the same number affected Taiwan. Nine tropical cyclones passed over the Philippines and six crossed the coast of Indo-China while two dissipated just off the coast. Four tropical cyclones struck Japan and one landed in Korea. The monthly distribution of tropical cyclone is shown in Figure 1 and a brief summary of their tracks is contained in Table 1. Six-hourly positions of the tropical cyclones together with the estimated minimum central pressures and maximum sμrface winds are also tabulated in the appendices. The monthly mean frequency of occurrence of tropical cyclones during the years 1947-1977 is given in Figure 2.
During the year there were twenty tropical cyclones in Hong Kong's area of responsibility for tropical cyclone warnings for shipping (i.e. the area bounded by 10°N, 30°N, 105°E and 125°E) compared with an average figure of seventeen in the past thirty-one years. Thirteen tropical cyclones moved into the area while seven developed within it. Altogether 506 warning tor shipping were issued by the Royal Observatory in connection with nineteen of these tropical cyclones and tropical cyclone warnings signals were displayed in Hong Kong to give warning about eight of them.
In 1978 rainfall in Hong Kong, is associated with tropical cyclones amounted to 1372.2 mm which is more than twice the annual average of 566.9:mm and represents more than half of the year's total rainfall of 2593.0 mm. Most of the rainfall was due to two tropical cyclones, Severe Tropical Storm Agnes in July with 519.0 mm and Severe Tropical storm Nina in October with 420.2 mm.
Typhoon Olive was the first tropical cyclone that formed in the year I 978. It developed on 17 April over the Caroline Islands and moved into the South China Sea threaten Hong Kong. This was the second time since 1947 that tropical cyclone warning signals were displayed in Hong Kong in April. Olive passed about 190 miles south-southeast of Hong Kong had little effect on the weather in Hong Kong.
There were no tropical cyclones in May but three tropical cyclones in June landed in Vietnam, Taiwan and western-Japan respectively.
Apart from Severe Tropical Storm Agnes there were three other typhoons in July. Typhoon Trix entered the east China coast near Shanghai; Typhoon Virginia passed close to the east coast of Japan and Typhoon Wendy crossed Kyushu and dissipated over the $ea· of Japan. Severe Tropical Storm Agnes approached Hong Kong twice (once from the· south and 3 days later from the southwest) and brought prolonged heavy rain. Agnes is unique in that it is the only tropical cyclone for which gale signals were hoisted on two separate occasions.
There were eight tropical cyclones over the western North Pacific and the South China Sea in August and tropical cyclone warning signals were hoisted for two of them. Typhoon Carmen crossed the Ryukyu Islands and later dissipated over Korea. Tropical Storm Della passed over Taiwan and degenerated into an area of low pressure near Xiamen (Amoy). One tropical depression landed in southern Japan while another two dissipated over the Pacific without encountering land.
Tropical cyclone warning signals were displayed in Hong Kong for Severe Tropical Storm Kit and Typhoon Lola in September. Two of the other five tropical cyclones in the month were unnamed and they both dissipated near the coast of north Vietnam. One of the remaining three landed in western Japan and the other two moved northward and eventually became extratropical well to the east of Japan.
Of the six tropical cyclones originated in October only Severe Tropical Storm Nina and Typhoon Rita came within three hundred miles of Hong Kong. The heavy rain associated with Nina caused many minor landslips and. floods in Hong Kong while the strong to gale force winds of Typhoon Rita overturned several small boats and, seriously affected air traffic. Typhoon Ora passed to the east of Taiwan and finally became an area of low pressure to the ·southeast of Japan. An unnamed tropical depression crossed the Philippines and dissipated off the coast of south Vietnam. Typhoon Phyllis and another tropical depression formed well to the east of the Mariana Islands and dissipated without encountering land.
The four tropical cyclones in November did not affect Hong Kong. One tropical depression landed in south Vietnam. The three others all originated near the Caroline Islands and dissipated over the Pacific. No tropical cyclones were reported over the western North Pacific or the South China Sea in December.