China's national observatory on Wednesday issued a blue alert for widespread rainstorms that are expected to sweep through the country's southern regions.

Some parts of Guizhou, Hunan, Jiangxi, Fujian provinces and the Guangxi Zhuang autonomous region will see heavy rains or rainstorms in the coming hours until 2 p.m. Thursday, the National Meteorological Center said.

Of these regions, western Hunan will be hit the hardest, with up to 130 millimeters of precipitation expected within the next 24 hours, the center said.

It warned local authorities to guard against possible geological disasters such as floods and landslides.

Meanwhile, the center said rain will hit some parts of north and northwest China over the next three days.

The national observatory uses a four-tier color-coded weather warning system, with red being the most severe, followed by orange, yellow and blue.