BEIJING - The National Marine Environmental Forecasting Center on Friday afternoon issued a blue wave warning for the South China Sea, anticipating the joint impact of a new tropical depression and a southwest monsoon.

According to the center, the tropical depression has moved northwest from the central area of the sea since Thursday and is expected to make landfall near the eastern coast of south China's Hainan Province between Friday night and Saturday morning in the form of a tropical storm.

From Friday night to Saturday daytime, the center forecast sea waves as high as 4 meters in the South China Sea, as well as waves ranging in height from 1.5 to 2.5 meters on the eastern coast of Hainan.

A blue warning for storm tides was also released for the area.

The center urged coastal units in the region to take precautions against the waves, calling on related maritime departments to strengthen levee patrols for potential safety risks.

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