Mercury to head south up north

Beijing residents can say goodbye to the recent warm weather - a cold front will hit northern China tomorrow, the Beijing meteorological center said yesterday.

"We may have to issue the first blue cold wave warning. We expect the temperature to drop by more than 10 C overnight," Guo Hu, director of the center, said at a press briefing yesterday.

A blue cold wave warning is issued when the temperature drops to 8 C and the windforce is 5 or above. Beijing will not be the only city to be hit, weather forecasters said.