China's national observatory on Saturday issued an orange alert, the second-highest in its four-tier system, for Typhoon Matmo, the 21st typhoon of the year, as it strengthens and heads toward the country's southern coast.

The typhoon, observed at 18 degrees north latitude and 117.7 degrees east longitude at 5 a.m. on Saturday, is moving northwestward at a speed of 25-30 km per hour, according to the National Meteorological Center (NMC).

It is anticipated to make landfall along coastal areas ranging from Dianbai in Guangdong Province to Wanning in Hainan Province, both located in south China, during the daytime on Sunday, the NMC said.

From Saturday morning to Sunday morning, the typhoon is expected to bring strong winds and heavy rain to China's southern coastal regions.

The national observatory has urged local authorities to activate emergency response measures for the typhoon and stay alert for mountain torrents and geological disasters triggered by heavy rainfall.

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