BEIJING, July 28 -- China's meteorological authority on Friday renewed a blue alert for severe convective weather in vast stretches of the country.

From 8 a.m. Friday to 8 a.m. Saturday, thunderstorms, gales, and hail will sweep parts of Heilongjiang, Tianjin, Jiangsu, Shanghai, Hubei, Zhejiang, and Fujian, said the National Meteorological Center.

Short bursts of heavy rainfall with hourly precipitation up to 80 millimeters will lash most regions of the country, including parts of Heilongjiang, Jilin, Liaoning, Gansu, Shaanxi, Hebei, Tianjin, Shandong, Henan, Anhui and Jiangsu, the center said.

It has recommended reducing outdoor activities. Vessels operating in or transiting affected waters should return to port or detour.

The center has also suggested checking drainage systems in cities, farmlands and fishponds, and making preparations for flash floods, landslides, mudslides and other disasters.

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