BEIJING -- China's national observatory on Friday morning issued an orange alert for Typhoon In-Fa, which has become a strong typhoon and is expected to make landfall in East China's Zhejiang province from Sunday afternoon to early Monday morning.

At 11 am Friday, the center of Typhoon In-Fa, which means fireworks, was located in a coastal area approximately 640 km southeast of Xiangshan in Zhejiang province, or at a latitude of 24.5 degrees north and a longitude of 125.3 degrees east, according to the National Meteorological Center.

It is moving northwestward at about 15 km per hour and gaining strength. In-Fa will bring rainstorms to regions including Shanghai, Zhejiang and Taiwan.

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