BEIJING, July 20 (Xinhua) -- China's national observatory on Friday issued a yellow alert for typhoon Ampil which strengthened before its forecast landfall in the eastern coastal region.

Ampil, this year's 10th typhoon, will make landfall in Zhejiang or Jiangsu as early as Saturday evening packing winds of up to 30 meters per second, the National Meteorological Center (NMC) said in a statement.

The tropical storm will weaken after reaching land and continue to move northwest inland, bringing downpours to a large swath of eastern and northern China, the NMC said.

Between Saturday and Monday, Zhejiang, Shanghai, Jiangsu, Anhui, Shandong, and Hebei will be battered by heavy rain under the influence of Ampil.

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

The NMC advised residents along the typhoon's path to stay indoors until it passes and warned of severe urban flooding.