Front and weather

A, according to the moving direction of cold and warm air mass, it can be judged that Figure A is a schematic diagram of a cold front. After the cold front passes, the temperature drops, the air pressure rises, and the weather is fine, which does not meet the meaning of the question;

B. According to the moving direction of cold and warm air masses, it can be judged that Figure A is a schematic diagram of a cold front. The cold air mass moves to the warm air mass actively, and the warm air mass is forced to rise to form precipitation, so it is correct;

C, according to the moving direction of the cold and warm air mass, it can be judged that Figure B is a schematic diagram of the warm front, and the warm air mass actively climbs to form continuous precipitation, which does not meet the meaning of the question;

D, according to the moving direction of the cold and warm air mass, it can be judged that Figure B is a schematic diagram of the warm front, and the warm air mass actively climbs to form continuous precipitation, which does not meet the meaning of the question.

So choose: B.