BEIJING - China's national observatory issued a blue alert, the lowest in a four-tier warning system, on Saturday for rainstorms in south China in the coming two days.

From Saturday to Sunday, heavy rain will sweep regions south of the Yangtze River, the National Meteorological Center (NMC) said in a statement.

Some areas will see torrential rain accompanied by thunder or hail, according to the NMC.

Local authorities were asked to prepare for emergencies, halt outdoor work and prevent floods and landslides.

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