TROPICAL CYCLONES IN 2007

Pabuk was the first tropical cyclone to necessitate the issuance of tropical cyclone warning signals in Hong Kong in 2007. It was the first No. 8 Gale or Storm Signal issued since the passage of Tropical Storm Kompasu in 2004. The track of Pabuk near Hong Kong was erratic. The Hong Kong Observatory had to issue tropical cyclone warning signals on two separate occasions. The last time this had happened was in 2000 when Severe Tropical Storm Maria affected Hong Kong.

Pabuk formed as a tropical depression over the western North Pacific about 1220 km southeast of Okinawa on the morning of 5 August and moved generally west-northwestwards. It intensified into a tropical storm that evening and further into a severe tropical storm the next day. Pabuk changed to a westerly track on 7 August. On the early morning of 8 August, it crossed the southern tip of Taiwan and entered the northeastern part of the South China Sea. While maintaining a westerly track, Pabuk slowed down and weakened into a tropical storm in the afternoon under the influence of Tropical Storm Wutip over the western North Pacific.

When Pabuk moved across the Luzon Strait, electricity supply to 3 000 families in Taiwan were cut off. Heavy rain south of Pabuk also brought landslides to the Philippines and resulted in 11 deaths.

Pabuk skirted the seas south of Hong Kong on the morning of 9 August and weakened further into a tropical depression. It changed to a southwesterly course that afternoon. After executing an anticlockwise loop just off Shangchuan Dao, Pabuk started to move northeast towards the Pearl River Estuary that night. On the morning of 10 August, Pabuk accelerated towards Hong Kong and intensified into a tropical storm again. It traversed the western part of Hong Kong and Deep Bay that afternoon but abruptly turned westwards and made landfall over Zhongshan, Guangdong in the evening. It weakened into a tropical depression and performed another looping motion to the west of Zhongshan that night. Pabuk weakened into an area of low pressure about 80 km northwest of Hong Kong on the morning of 11 August.

In Hong Kong, the Standby Signal No. 1 was first issued at 5.40 a.m. on 8 August when Pabuk was about 550 km to the east of Hong Kong. The outer rainbands of Pabuk brought squally showers and thunderstorms to Hong Kong on the evening of 8 August. With Pabuk coming closer to Hong Kong, the Strong Wind Signal No. 3 was issued at 2.40 a.m. on 9 August when Pabuk was about 90 km east-southeast of the Observatory. Locally, winds were generally strong with squally showers and brief periods of gales over the southern part of Hong Kong and on high grounds on the early morning of 9 August. As Pabuk moved away from Hong Kong, all signals were cancelled at 11.15 a.m. on 9 August.

As Pabuk suddenly changed its direction of movement and edged towards Hong Kong on the morning of 10 August, the Standby Signal No. 1 was issued again at 7.50 a.m. when Pabuk was about 110 km to the southwest. As Pabuk picked up speed and intensified into a tropical storm, the No. 3 Strong Wind Signal was issued at 12.40 p.m. that day, followed by the No.8 Southwest Gale or Storm Signal at 2.30 p.m. Pabuk was closest to the Hong Kong Observatory Headquarters at around 2.30 p.m. when it was crossing the western part of Hong Kong about 30 km to the west-northwest. Winds over Hong Kong strengthened significantly with gales affecting the western part of Hong Kong and offshore waters during the afternoon and evening. When Pabuk weakened into a tropical depression and moved away from Hong Kong, the No.8 Southwest Gale or Storm Signal was replaced by the No. 3 Strong Wind Signal at 9.40 p.m. This was followed by the No.1 Signal at 1.40 a.m. on 11 August as local winds moderated further. All signals were cancelled at 8.30 a.m. that morning. Squally showers affected Hong Kong on 10 August and early on 11 August.

During the passage of Pabuk, the lowest instantaneous mean sea-level pressures recorded at some selected stations were as follows :-

In Hong Kong, two men fell into the sea after a section of scaffolding they were erecting under a flyover in Castle Peak Road collapsed. One of them was drowned and the other injured. There were 16 other injured from fallen objects in various parts of Hong Kong. A total of 33 reports of fallen trees were received. Two aircraft were diverted.

Information on maximum wind, daily rainfall and maximum sea level during the passage of Pabuk is given in Tables 3.1.1 - 3.1.3. Figures 3.1.1 - 3.1.6 show the track of Pabuk, rainfall distribution, satellite and radar imageries of Pabuk, pressure recorded at the Hong Kong International Airport and wind distribution in Hong Kong respectively.

- Top -