weather signal

A, the north side of a is low pressure, which can't be northwest wind, which doesn't conform to the meaning of the question;

B, according to the front airflow movement in the picture, it is a warm front. A is in the front and back, south. According to this map, it is a map of the southern hemisphere, and the wind deflects to the left, so the wind direction is southeast wind, not southwest wind, which does not meet the meaning of the question;

C, according to the front airflow movement in the figure, it is a warm front. A is in the south and rear of the front, which does not meet the meaning of the question;

D, according to the front airflow movement in the picture, it is a warm front. A is in the front and back, south. According to this map, it is a map of the southern hemisphere. The wind deflects to the left, so the wind direction is southeast, so it is correct.

Therefore, choose: d.