Tropical Cyclones in 2020 > Report on Tropical Storm Sinlaku (2003): 31 July to 2 August 2020

3.2 Tropical Storm Sinlaku (2003): 31 July to 2 August 2020

Sinlaku was the second tropical cyclone affecting Hong Kong in 2020.

A monsoon depression entered the South China Sea on 30 July and developed into a tropical depression the next night. The tropical depression generally tracked west-northwestward towards Hainan Island and was named Sinlaku on the afternoon of 1 August. Sinlaku intensified into a tropical storm over Beibu Wan in the small hours of the next day and reached its peak intensity with an estimated maximum sustained wind of 65 km/h. It made landfall over the northern part of Vietnam on the morning of 2 August and weakened into an area of low pressure over inland Vietnam that night.

The Strong Monsoon Signal was issued by the Hong Kong Observatory at 7:05 a.m. on 31 July. Under the combined effect of the subtropical ridge and outer circulation of the monsoon depression, local winds were generally strong easterlies with occasionally gales offshore and on high ground on that day. With the monsoon depression developing into a tropical depression, the Strong Wind Signal No. 3 was issued to replace the Strong Monsoon Signal at 8:40 p.m. on 31 July when Sinlaku was about 550 km south-southwest of Hong Kong. This was the sixth time on record that the Strong Wind Signal No. 3 was issued directly to replace the Strong Monsoon Signal. The last time it happened was in 1993 due to Typhoon Dot. Local winds were generally strong east to southeasterlies on the night of 31 July and during the day on 1 August with occasionally gales offshore and on high ground. With Sinlaku moving further away from Hong Kong, local winds subsided gradually and the Strong Wind Signal No. 3 was replaced by the Standby Signal No.1 at 9:10 p.m. on 1 August. All tropical cyclone warning signals were cancelled at 11:15 p.m. at night.

Under the influence of Sinlaku, a maximum sea level (above chart datum) of 2.91 m and a maximum storm surge of 0.54 m (above astronomical tide) were recorded at Tsim Bei Tsui and Tai Po Kau respectively. At the Observatory Headquarters, the lowest instantaneous mean sea-level pressure of 1003.0 hPa was recorded at 2:57 a.m. on 1 August.

Affected by the outer rainbands of Sinlaku, there were occasional squally heavy showers and thunderstorms on 31 July and 1 August. More than 70 millimetres of rainfall were generally recorded in Hong Kong during these two days.

There were a number of reports of fallen trees in Hong Kong during the passage of Sinlaku. Incidents of blowing down objects were also reported in many places. In Tsim Sha Tsui, two people were injured by a fallen tree while hoarding boards toppled by strong winds also caused one person injured and two vehicles damaged. A canopy in Kwun Tong and scaffolding in Tseung Kwan O collapsed under high winds. In Pok Fu Lam, some plastic fences were blown away and wounded a passer-by.