Four-curve weather

A, ① is a warm front, because the warm air mass climbs slowly along the cold air mass, forming continuous precipitation, so it does not meet the meaning of the question;

B and ② are anticyclones, the airflow sinks in the vertical direction, the temperature of the airflow rises during the sinking process, the water vapor is not easy to condense, and the weather is fine, so it is correct;

C and ③ are cold fronts, and the front edge of the cold air mass is inserted under the warm air mass and forced to rise, so the water vapor in it is easy to condense into clouds and cause rainfall, which does not meet the meaning of the question;

D and ④ are cyclones, the airflow rises vertically, and it is easy to condense clouds in the process of airflow rising, causing rainfall, which does not meet the meaning of the question.

Therefore, choose: B.