TROPICAL CYCLONES IN 2004

Kompasu was the only tropical cyclone to necessitate the issuance of No. 8 Gale or Storm Signal in the year.

Kompasu developed as a tropical depression over the Pacific about 620 km east-southeast of Gaoxiong on the early morning of 14 July. Moving westwards, Kompasu intensified into a tropical storm that afternoon and crossed the Luzon Strait. Upon entering the South China Sea, it adopted a northwestward course and headed towards the coast of Guangdong. It turned north-northweastwards and made landfall over Hong Kong on 16 July. Kompasu weakened into a tropical depression and dissipated over inland Guangdong that evening. In Guangdong, many trees were uprooted and signboards collapsed. Ferry services between Guangdong, Hong Kong and Macao were suspended.

In Hong Kong, the Standby Signal No. 1 was issued at 10.55 p.m. on 14 July when Kompasu was 720 km to the east-southeast of Hong Kong. With Kompasu moving closer to Hong Kong and winds strengthening, the Strong Wind Signal No. 3 was issued at 5.15 a.m. on 16 July. Showers set in as Hong Kong began to come under the influence of Kompasu's spiral rainbands. Local winds reached gale force at Waglan Island later that morning. The No. 8 NORTHEAST Gale or Storm Signal was issued for the first time this year at 11.45 a.m.

Kompasu made landfall over Sai Kung at around 3.00 p.m. on 16 July when it was 25 km to the east of Hong Kong Observatory Headquarters, its closest approach. Following landfall Kompasu traversed the northeastern part of the New Territories. The No. 8 NORTHWEST Gale or Storm Signal and No. 8 SOUTHWEST Gale or Storm Signal were issued at 2.45 p.m and 4.45 p.m respectively. With Kompasu beginnnig to move away and local winds gradually subsiding, the No. 8 Signal was replaced by the Strong Wind Signal No. 3 at 7.20 p.m. on 16 July. All tropical cyclone warning signals were cancelled an hour later.

During the approach of Kompasu, a maximum hourly mean wind of 47 km/h and a maximum gust of 79 km/h were recorded at Tap Mun on the afternoon of 16 July. At Waglan, a maximum hourly mean wind of 88 km/h and a maximum gust of 106 km/h were recorded. The lowest instantaneous mean sea-level pressures recorded at Hong Kong Observatory Headquarters, Waglan Island and Ta Kwu Ling were 1 000.5 hPa, 995.7 hPa and 1 001.0 hPa respectively.

The rainbands and remnant of Kompasu brought heavy squally showers to Hong Kong on the afternoon of 16 July and on the following day. The Amber Rainstorm Warning Signal was in force between 5.00 p.m. and 6.50 p.m. on 16 July, and between 2.20 a.m and 3.30 a.m. on 17 July. More than 120 millimetres of rainfall were recorded at the Observatory Headquarters.

Locally, 12 people were injured during the passage of Kompasu. Among them two were hit by fallen objects, one in North Point and another in Tsuen Wan. Minor flooding was reported at Lockhart Road in Wan Chai. There was one report of fallen concrete at Belcher's Tower in Western District and two reports of collapsed scaffolding at Cyberport and Kowloon City Road. A total of 19 cases of fallen trees was reported. At the Hong Kong International Airport, 13 flights were delayed and two were cancelled. Ferry services were suspended.

Information on maximum wind, daily rainfall and maximum sea level during the passage of Kompasu is given in Tables 3.2.1 - 3.2.3. Figures 3.2.1 and 3.2.2 show the track of Kompasu and the rainfall distribution respectively. Time series of the wind speed recorded at Waglan Island and Tai Mei Tuk are given in Figure 3.2.3. The cyclonic circulation of Kompasu wind field is shown in Figure 3.2.4. Traces of the pressure recorded at Waglan Island and Ta Kwu Ling are given in Figure 3.2.5. Figures 3.2.6 and 3.2.7 are respectively the satellite and radar imageries of Kompasu.

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