BEIJING - China's top meteorological authority issued a rainstorm alert on Saturday, warning of torrential rains to hit the southern regions till Sunday morning.

Yunnan province, Guangxi Zhuang autonomous region, and some areas of Jiangsu and Anhui provinces in particular, will see heavy rainstorms. Precipitation in these regions is forecast to reach a maximum of 300 mm, the National Meteorological Center (NMC) forecast.

Meanwhile, some areas in the provinces of Guizhou, Sichuan, Hunan, Hubei, Shaanxi and Henan will also see torrential rains, according to the forecast.

Local authorities were urged to step up preparatory work against possible mountain floods, landslides, and mud-rock flows.

The NMC said that the stormy weather is due to joint influence of the southwest monsoon and typhoon Trami, which had already weakened and been downgraded to a tropical depression on Friday.

Rainstorms brought by Typhoon Trami swept the coastal provinces of Zhejiang and Fujian, affecting 1.4 million people and forcing relocation of 351,000 since it made landfall early Thursday morning.

It also affected 361,000 people in central China's Hunan province and of all, 30,900 were displaced, local authorities said Saturday.