The Hong Kong Observatory cancelled the amber rainstorm warning for a second time on Saturday, after the city was hit by heavy showers and thunderstorms under the combined influence of a southwest monsoon trough and a low-pressure trough.

The earlier downpours prompted the forecaster to issue an amber rainstorm warning – the lowest in the three-tier system – at 5am, before cancelling it at 8.45am. The signal was issued again at 2.15pm then cancelled at 3.40pm.

More than 30mm (1.3 inches) of rainfall was recorded in many areas during the morning.

Tsuen Wan was among the worst hit, recording 70mm of rain – a level comparable to the threshold for a top-tier black rainstorm warning.

The Observatory earlier warned of possible flash floods, urging people to stay away from watercourses and advising drivers to be alert.