In zones where air ascends, the air is less dense than its surroundings
and this creates a center of low pressure. Winds blow from areas of high
pressure to areas of low pressure, and so the surface winds would tend
to blow toward a low pressure center.
In zones where air descends back to the surface, the air is more
dense than its surroundings and this creates a center of high
atmospheric pressure. Since winds blow from areas of high pressure to
areas of low pressure, winds spiral outward away from the high
pressure. The Coriolis Effect deflects air toward the right in the
northern hemisphere and creates a general clockwise rotation around the
high pressure center. In the southern hemisphere the effect is just the
opposite, and winds circulate in a counterclockwise rotation about the
high pressure center. Such winds circulating around a high pressure
center are called anticyclonic winds and around a low pressure
area they are called cyclonic winds.