The city woke up to yet another amber rainstorm on Sunday morning as a low pressure trough continued to swirl above southern China, bringing unsettled weather to the region.
The Hong Kong Observatory raised an amber signal at 7.55am, an hour after a thunderstorm warning was issued, as 30 to 50 millimetres of rain per hour battered parts of the city. It cancelled the signal at noon.
In the northern New Territories, rainfall hit more than 115mm in four hours, prompting the Observatory to issue an urgent flooding announcement.
Sheung Shui, Sha Tau Kok, Lau Fau Shan and Tai Po were hit worst.
The Observatory warned of possible flooding in low-lying and poorly drained and urged those likely to be affected to take necessary precautions. Flash flooding could also occur near watercourses, the weatherman added.
Red flags, due to big waves, were hoisted by the Leisure and Cultural Services Department at multiple beaches including Shek O in Southern District and Clear Water Bay First Beach in Sai Kung.
Weather conditions should improve slightly after Monday.
On Saturday afternoon, the Observatory recorded 10mm of rainfall and detected lightning over Lantau, Lamma and Hong Kong Island. The thunderstorm signal was raised for three hours, and gusts of over 70km/h were recorded.
On Thursday, when the year's second black rainstorm signal was issued, the Observatory recorded rainfall of 106.33mm. The junction of Leighton Road and Morrison Hill Road in Causeway Bay was one of the worst-hit spots, with passengers stranded on broken-down buses forced to wade across flooded roads. An online video also showed flooding in the Cross-Harbour Tunnel. Some bus passengers were reported to have disembarked and walked out of the tunnel.
Owners of shops on Ma Tau Wai Road, To Kwa Wan, complained that drains blocked by construction work from the Sha Tin-Central rail link had caused flooding, but the MTR Corporation denied responsibility.
Heavy rain continued to fall on Friday, with an amber rainstorm signal raised briefly on Friday night. Some 89.1mm of rain was recorded.
The first black rainstorm alert of the year was issued on March 30, when hailstones hammered parts of Kowloon and the New Territories. The MTR said it caused flooding in a Yuen Long construction site for the high-speed railway linking the city and Shenzhen, and damaged a tunnel-boring machine. The opening date of the railway has now been postponed by two years to 2017.