The amber rainstorm warning signal was hoisted twice in Hong Kong on Saturday as heavy rain drenched the city.

The Hong Kong Observatory said it will be cloudy with occasional showers and squally thunderstorms, as a southerly airstream was affecting the coast of Guangdong and thundery showers were also affecting the region.

The alert  – the lowest in the city's three-tier rainstorm alert system – indicates that heavy rain has fallen or is expected to fall generally over Hong Kong, exceeding 30 millimeters in an hour, and is likely to continue.

The first amber alert of the day was hoisted at 5 am and cancelled at 8:45 am. The HKO issued amber alert again at 2:15 pm.

“Under the influence of an active southwest monsoon and a trough of low pressure, local weather will continue to be unsettled in the next few days,” the observatory said in a special weather bulletin.

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It warned showers will be particularly heavy over some areas on Sunday and Monday and accumulated rainfall may reach 200 millimeters in two days, according to the observatory.

The weather will remain unsettled midweek next week as the trough of low pressure was expected to linger persistently over the vicinity of the coast of Guangdong and the northern part of the South China Sea, the city’s weather agency said.

Showers will lessen and the weather will improve gradually towards the weekend, with the subtropical ridge over the western North Pacific extending westwards in the latter part of next week, according to the observatory.