Dark cloud is seen over downtown Shanghai, east China, Aug. 31, 2010. Heavy rains and thunderstorms are predicted to hit Shanghai as this year's six, seventh and eighth tropical storms are active at sea in east China.

Shanghai authorities Tuesday canceled all kindergarten, primary and high school classes for Wednesday because of typhoon Kompasu.

The decision aims to ensure students' safety as the typhoon is likely to bring heavy rains and strong gales from Tuesday evening until Wednesday.

Wednesday is the beginning of the autumn semester for schools across China. In Shanghai, the new semester will now start on Thursday.

Kompasu is packing wind gusts of 144 kilometers per hour near its center. It is moving northwest at a speed of 30 kilometers per hour and will enter the East China Sea Tuesday night.

Meteorological authorities issued a typhoon warning Tuesday afternoon, warning relevant authorities to prepare for strong winds and downpours at the Shanghai World Expo site.

Dark cloud is seen over downtown Shanghai, east China, Aug. 31, 2010. Heavy rains and thunderstorms are predicted to hit Shanghai as this year's six, seventh and eighth tropical storms are active at sea in east China.