The Hong Kong Observatory recently adjusted their forecast about the number of tropical cyclones entering 500 km of Hong Kong this year to six to nine, which means there may be three more to come.
"We expected, for the rest of this year, the number of tropical cyclones entering the 500-kilomoeter range of Hong Kong are likely to be normal," Tong Hang Wai, Scientific Officer of the Hong Kong Observatory, told Xinhua on Wednesday.
He said, however, taking the actual observations in January to August into account, the number of typhoon is already higher than normal, and so there is a need to adjust.
In March, the observatory expected four to seven tropical cyclones coming within 500 km of Hong Kong, which is near normal. The forecast is, however, now adjusted to six to nine.
This year, six tropical cyclones entered the 500-km range of Hong Kong thus far, namely Merbok, Roke, Haitang, Hato, Pakhar and Mawar. Four of them necessitated the issuance of tropical cyclone warning signals of No. 8 or higher.
A hurricane signal No. 10, the highest level, was issued on Aug. 23, 2017, when typhoon Hato coincided with high tide battered Hong Kong, causing servere flooding in low-lying areas, hundreds of trees collapsed and transportation came to a halt.
In less than a week after Hato left, another typhoon, Pakhar hit Hong Kong and signal No. 8 was hoisted.
Hong Kong's typhoon season usually falls in summer. But Tang said it is not uncommon in Hong Kong to have typhoons in autumn and winter. Records showed that typhoon signals No. 8 were hoisted in November in 1954 and 1972.
Since the long-term averages of the number of tropical cyclones entering 500 km of and affecting Hong Kong are roughly the same, the forecast of the former is, to some extent, indicative of the latter, according to the Observatory.
The forecast about Hong Kong's annual rainfall was also adjusted, from 2,000 to 2,600 millimeters to 2,300 to 2,900 millimeters. Up to Aug. 31, 2017, the rainfall recorded at the observatory this year is 2,249 millimeters, about 18 percent above the normal value for the same period.
The observatory's latest climate model predictions indicated that rainfall in Hong Kong is likely to be normal to below normal for the rest of this year.
