BEIJING, Aug. 1 (Xinhua) -- China's national observatory on Wednesday issued a blue alert for typhoon Jongdari which strengthened before its forecast landfall in the eastern coastal region.

Jongdari, this year's 12th typhoon, will make landfall at the coast between Xiangshan of Zhejiang Province and Qidong of Jiangsu Province as early as Friday morning, packing winds of up to 82.8 kilometers per hour, the National Meteorological Center (NMC) said in a statement.

At 3 p.m. Wednesday, the eye of Jongdari was 445 km offshore from the city of Zhoushan, Zhejiang Province.

The tropical storm will weaken after reaching land and continue to move northwest inland, the NMC said.

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

The NMC suggested local governments take precautions against disasters, ships in affected areas should return to port, and residents along the typhoon's path are urged to stay indoors until it passes.