BEIJING - China's meteorological authority issued a blue alert on Saturday for a typhoon expected to hit the southern province of Guangdong, while warning of mountain floods in the southwest due to torrential rains.

The country's fourth typhoon this year was detected 510 km off the coast of Manila at 5:00 p.m. Saturday and will land in Guangdong on Tuesday, the National Meteorological Center (NMC) said.

The wind speed could reach 38-45 meters per second when the typhoon makes landfall, according to the NMC.

It also warned that heavy rain could lead to mountain floods in parts of southwest China's Tibet Autonomous Region and Sichuan Province from Saturday night to Sunday night.

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