BEIJING, May 12 (Xinhua) -- China's national observatory said Saturday that moderate to heavy rain would sweep most parts of southern China in the next three days.

The National Meteorological Center forecast downpours and rain storms in Guizhou, Yunnan, Guangxi and Guangdong until Sunday, with some areas seeing thunderstorms and gales. A number of other southern areas, including coastal areas, will also see rainfall.

The rain will then gradually ease off.

Northwest China's Xinjiang will see its northern parts hit by torrential rain from Saturday. The center cautioned against floods, landslides and loose debris in Xinjiang's mountainous regions.

The center also issued a blue alert for severe convection in northern China, which will bring strong winds and hail in areas including Beijing, Tianjin, Hebei and Shandong on Saturday and Sunday.

China has a four-tier color-coded weather warning system, with red the most severe, followed by orange, yellow and blue.