China's national observatory on Wednesday upgraded the alert for Typhoon Doksuri to the highest level of red, as the fifth typhoon this year is expected to bring gales and downpours to the southern and eastern parts of the country.

The upgrade was made by the National Meteorological Center only four hours after it issued an orange alert at 6 am.

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

The typhoon, observed over the ocean about 350 kilometers south of Taiwan at 8 am Wednesday, is expected to move northwest at a speed of 10 to 15 km per hour, the center said in a media release.

Forecast shows that the cyclone will enter the northeastern part of the South China Sea between Wednesday evening and Thursday morning and then make landfall in coastal areas of Fujian and Guangdong provinces on Friday morning.

Aside from raging a vast stretch of sea areas, including parts of Bashi Channel and the South China Sea, it said, gales the typhoon brings will also strike Taiwan island and coastal areas of Fujian.

It said the Taiwan island and the eastern part of Zhejiang province will experience heavy downpours over 24 hours starting 2 pm Wednesday. The precipitation in some areas in the eastern and southern parts of Taiwan are expected to reach 250 to 400 millimeters during the time.