HAIKOU, Nov. 2 (Xinhua) -- South China's Hainan Province on Monday morning issued a Level-4 alert for Typhoon Swan, which is expected to bring torrential downpours and strong winds to parts of the region.

Swan, the 19th typhoon of the year, was in the South China Sea Sunday night and was observed some 100 km southeast of Huangyan Island, at 6 a.m. Monday, with winds of 82.8 km per hour near the eye, according to the provincial meteorological center.

The typhoon is forecast to move northwestward at a maximum speed of 20 km per hour and gradually weaken, the center said.

The center also said a cold front will bring heavy rainfall to waters off the coast of Hainan from Monday to Thursday, accompanied by wind gusts.

Hainan has a four-tier typhoon warning system, with Level 1 representing the most severe weather.