China’s Guangdong coast was placed on heightened alert on Wednesday as Typhoon Saudel strengthened over the South China Sea and was forecast to make landfall or pass close to the coast between Thursday afternoon and Friday morning.

Authorities warned of heavy rainfall, gale force winds and severe storms, with concerns over flooding and other weather-related damage.

Several cities have suspended classes, and coastal authorities have been instructed to take measures to protect people and limit economic losses.

A yellow typhoon warning was issued in Nan’ao county at noon on Wednesday, while blue warnings were activated in areas including Chaozhou, Zhejiang, Shandong and Zhuhai.

The Nan’ao Bridge, which connects the island to the mainland, was closed to traffic from 2pm. Authorities said it would reopen depending on weather conditions.

At 8am on Wednesday, Saudel was about 195 kilometres east southeast of Shanwei in the northeastern South China Sea. The National Meteorological Centre said the storm had maximum winds of 18 metres per second, with stronger winds extending up to 300 kilometres from its centre.

Saudel was expected to turn westward and move along the Guangdong coast from Thursday. Forecasters said its projected path increased the possibility of landfall or a close passage between Shantou and Huizhou.