Hong Kong has been hit by more heavy showers and thunderstorms as a trough of low pressure moved over the Pearl River Estuary.The downpours prompted the Hong Kong Observatory to issue an amber rainstorm warning – the lowest in a three-tier system – at 5am on Saturday, before cancelling it at 8.45am.More than 30mm 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...