TROPICAL CYCLONES IN 2016

3.1 Tropical Depression: 26 – 27 May 2016

The formation of a tropical depression over the northern part of the South China Sea led to the issuance of tropical cyclone warning signals by the Hong Kong Observatory for the first time in 2016.

After formation over the northern part of the South China Sea on the night of 26 May, the tropical depression moved north-northwestwards and edged closer to the coast of western Guangdong. It took on a more northerly track the next day and slightly intensified, reaching peak intensity with an estimated sustained wind of 55 km/h near its centre. It made landfall near Yangjiang in western Guangdong on the evening of 27 May and soon degenerated into an area of low pressure that night. According to press reports, the tropical depression brought rainstorms to western Guangdong. A bridge was destroyed by flood, causing a bus to plunge into the river and injuring two persons. At the Macao Maritime Ferry Terminal, two passengers were injured during an incident of vessel collision.

After the formation of the tropical depression about 370 km south-southwest of Hong Kong on 26 May, the Hong Kong Observatory issued the Standby Signal No. 1 at 9:40 p.m. that evening. Winds were moderate to fresh easterly winds in Hong Kong overnight. As the tropical depression moved northwards and edged closer to the coast of western Guangdong, the Strong Wind Signal No. 3 was issued at 5:40 a.m. on 27 May. Under the influence of the outer rainbands of the tropical depression, winds reached strong force over many places in the territory around noon time. As the chance of having generally strong winds in Hong Kong subsequently receded, the Strong Wind Signal No. 3 was replaced by the Standby Signal No. 1 at 1:40 p.m. Fresh south to southeasterlies generally affected Hong Kong in the afternoon, occasionally reaching strong force over the western part or the territory. At the Observatory Headquarters, the lowest instantaneous mean sea-level pressure of 1004.7 hPa was recorded at 5:40 p.m. when the tropical depression was making landfall over coast of western Guangdong about 190 km west of Hong Kong. The tropical depression was closest to the territory at around 8 p.m., passing about 170 km to the west. As it soon degenerated into an area of low pressure over western Guangdong, all tropical cyclone warning signals were cancelled at 10:50 p.m. that night.

The tropical depression did not cause any significant damage in Hong Kong during its passage. Its outer rainbands brought occasional squally showers on 27 May and more than 10 mm of rainfall were generally recorded over the territory. A maximum sea level of 2.67 m (above chart datum) was recorded at Tsim Bei Tsui, while a maximum storm surge of 0.47 m (above astronomical tide) was recorded at Tai Po Kau.

Information on the maximum wind, period of strong winds, daily rainfall and maximum sea level reached in Hong Kong during the passage of the tropical depression is given in Tables 3.1.1 - 3.1.4 respectively. Figures 3.1.1 - 3.1.4 show respectively the track of the tropical depression, the rainfall distribution for Hong Kong, a satellite imagery and a related radar imagery of the tropical depression.