BEIJING, May 31 -- China's national observatory has issued a blue alert for rainstorms in southern and eastern provinces over the next three days.

The National Meteorological Center forecast heavy rain for Jiangsu, Anhui, Hubei, Zhejiang, Jiangxi, Hunan, Sichuan, Guizhou, Shanghai and Chongqing.

Some of these regions are expected to see up to 180 mm of rain within 24 hours.

The observatory urged local authorities to step up preparatory work against possible mountain floods, landslides and mud-rock flows.