Severe Tropical Storm Bailu(1911)
Severe Tropical Storm Bailu (1911)
21 to 26 August 2019
Bailu was the third tropical cyclone affecting Hong Kong in 2019.
Bailu formed as a tropical depression over the western North Pacific about 1460 km east-southeast of Gaoxiong on the afternoon of 21 August and drifted westwards at first. Bailu intensified into a tropical storm on 22 August and started to take on a northwesterly course towards the southern part of Taiwan in the afternoon. Bailu further intensified into a severe tropical storm that night. It reached its peak intensity on the night of 23 August with an estimated maximum sustained wind of 105 km/h near its centre. After sweeping across the southern part of Taiwan on 24 August, Bailu moved across the Taiwan Strait. It made landfall over Fujian the next morning and weakened into a tropical storm. Bailu moved further inland during the day and weakened into an area of low pressure over inland Guangdong on the small hours of 26 August.
After Bailu sweeping across the southern part of Taiwan on 24 August, the Hong Kong Observatory issued the Standby Signal No. 1 at 2:40 p.m. when Bailu was about 650 km east of Hong Kong. Local winds were moderate to fresh westerly. Affected by the outer subsiding air of Bailu, the weather was very hot with haze in Hong Kong in the afternoon. Bands of intense thundery showers associated with Bailu brought frequent thunderstorms and squalls to Hong Kong on the small hours of 25 August. Gusts of 104 and 85 km/h were once recorded at Cheung Chau Beach and Tai Po Kau respectively. Nearly 4000 cloud-to-ground lightning strokes were also recorded in Hong Kong between midnight and 2 a.m. on 25 August. The Amber Rainstorm Warning Signal was issued by the Observatory. Although Bailu moved inland and weakened during the day on 25 August, it still edged closer to Hong Kong. Local winds were moderate to fresh southwesterly during the day, occasionally reaching strong force offshore and on high ground. With Baliu weakening further and local winds moderating, all tropical cyclone warning signals were cancelled at 7:20 p.m. on 25 August. Bailu came closest to Hong Kong at around 8 p.m. on 25 August when it was around 280 km north of the territory. The rainbands associated with Bailu brought heavy downpour and squally thunderstorms to Hong Kong in the small hours on 26 August, necessitating the issuance of the Red Rainstorm Warning. Overall, more than 150 millimetres of rainfall were generally recorded over most parts of the territory on 25 and 26 August, with rainfall exceeding 250 millimetres over the urban areas.
Under the influence of Bailu, a maximum sea level (above chart datum) of 2.27 m and a maximum storm surge (above astronomical tide) of 0.22 m were recorded at Tsim Bei Tsui. The lowest instantaneous mean sea-level pressure of 999.0 hPa was recorded at the Observatory headquarters at 3:07 a.m. on 25 August.
When Hong Kong was hammered by frequent squally thunderstorms on the small hours of 25 August, the overhead cables of the East Rail of MTR were damaged by fallen trees, causing disruption to the train services. The power supply over many places was also affected because of the voltage dip.
According to press reports, Bailu caused at least one death and nine injuries to Taiwan during its passage. Over 100 000 households were without electricity supply. In Fujian, electricity supply to over 440 000 households was also interrupted. Air and land transportations were affected.