If the air sinks, it warms and the liquid water evaporates causing clouds to dissipate. Air moves out away from the center of high pressure. Air must come down from above to replace the air moving away from the high. Thus there is a general sinking or subsidence of air in a high pressure area. High pressure generally brings dry fair weather.
Air is pushed toward a low pressure center.
The converging air is forced upward. Low pressure is generally associated with cloudy or stormy weather. Argonne National Laboratory, Division of Educational Programs, Harold Myron, Ph.D., Division Director.