Tropical storm Krosa developed into a strong typhoon in the western Pacific on Thursday as it moved northwest at 15 km per hour and is forecast to come closest to Shanghai from October 7 to 8, according to a report from the China Meteorological Administration (CMA).

Torrential rainfall and strong winds are forecast to hit Shanghai and China's eastern and southern costal provinces, including Guangdong, Fujian and Zhejiang in the coming days.

The strongest gale force winds in Shanghai's downtown area are forecast to reach a scale of 7 to 8.