BEIJING, Nov. 13 (Xinhua) -- China's national observatory on Friday renewed a blue alert for Typhoon Vamco, which is expected to bring downpours and strong winds to parts of southern China's coastal areas.

The center of Vamco, the 22nd typhoon of the year, was about 370 km southeast of Sansha City, Hainan Province, at 9 a.m. Friday morning, with winds of up to 118.8 km per hour near the eye, according to the National Meteorological Center (NMC).

The typhoon is forecast to move westward at a speed of around 20 km per hour, passing through the Zhongsha and Xisha islands before landing at the central and northern coast of Vietnam.

From Friday afternoon to Saturday afternoon, gales are expected to hit parts of the Taiwan Strait, the Bashi Channel, the Qiongzhou Strait, Beibu Gulf and the South China Sea.

Affected by the typhoon, the eastern part of Hainan Province is expected to experience heavy rainfall within 24 hours, according to the NMC.

The NMC has advised people and vessels in at-risk areas to shelter from winds.

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