Typhoon Nakri moved into the Yellow Sea at a speed of 15 kilometers per hour on Saturday morning, said China's National Marine Environmental Forecasting Center.
Waves as high as 4 to 6 meters are expected in the north of the East China Sea and south of the Yellow Sea from Saturday noon to Sunday midday, with a yellow alert issued by the center.
China has a four-tier weather warning system, with red representing the most severe, followed by orange, yellow and blue.
Waves as high as 3.5 meters will be seen off the coastal areas of Jiangsu, Shanghai and Shandong, the center said, warning vessels to take precautions.