Typhoon Saola was expected to make landfall in southern China late Friday or early Saturday, hours before another tropical cyclone’s expected landfall along the country’s east coast, forecasters said.

Forecasters expect Saola to make landfall in the southern Chinese province of Guangdong, the state-controlled news media reported. Public transportation will be suspended on Friday evening in Shenzhen, a coastal megacity there.

Saola was about 105 miles east-southeast of nearby Hong Kong on Friday, the Chinese territory’s meteorological agency said in a warning. It was expected to draw within about 31 miles of the territory late Friday and into Saturday. Water levels in Hong Kong were already higher than normal, the agency said, adding that serious flooding could occur as the storm got closer.

A second Pacific typhoon, Haikui, was forecast to make landfall in eastern China, south of the city of Wenzhou, on Sunday, the United States Embassy in Beijing said in a weather alert. It said southern and eastern China could see damaging winds, heavy rains, flooding, mudslides and travel disruptions through Monday.

As of Thursday, southern China was under the highest level of alert under a four-tier typhoon warning system. A number of trains and ferries serving Guangdong were expected to be canceled or rerouted.

Typhoon Saola was generating sustained winds of 138 miles per hour on Friday, according to the Joint Typhoon Warning Center, a meteorological service operated by the U.S. Navy. That would make it a Category 4 storm on the five-tier wind scale that is used to measure tropical cyclones in the Atlantic.

Typhoon Haikui had maximum sustained winds of about 80 m.p.h., the center said, making it a weak Category 1 storm.

Hurricanes and typhoons are tropical cyclones with sustained winds of at least 74 m.p.h. The term “hurricane” refers to tropical cyclones in the Atlantic basin; “typhoon” refers to ones that develop in the northwestern Pacific and affect Asia.

Dozens of people died in northern and northeastern China during heavy flooding earlier this summer.

Typhoon Saola, named for an elusive species of wild ox that is native to parts of Southeast Asia, has been moving through the region for days. It prompted evacuations in the Philippines and school closings and travel disruptions in Taiwan, but it has not been linked to any deaths or injuries.

There is consensus among scientists that tropical cyclones are becoming more powerful because of climate change, and that the likelihood of major ones is increasing. Climate change is also affecting the amount of rain that storms can produce.

Keith Bradsher contributed reporting.