Based on the current phenological phase observation data and weather forecast analysis, it is expected that pear blossoms in urban areas of Shijiazhuang City will enter the first flowering period from April 8 to 9 this year, and in suburban counties

A. ① is the air circulation formed due to uneven cold and heat on the ground, so it is correct;

B. ② is the foehn phenomenon, so it does not meet the meaning of the question;

C. The airflow in the vertical direction at ③ is sinking, which is an anticyclone, so it does not meet the meaning of the question;

D. The cold air mass at ④ actively moves towards the warm air mass to form a cold front. Therefore it does not meet the meaning of the question.

So choose: A.