An area is considered to have high barometric pressure when it has greater atmospheric pressure than the surrounding area. Normal barometric pressure is between 980 millibars and 1,050 millibars. High pressure systems are also referred to as anticyclones.
High pressure systems move in a clockwise motion in the Northern Hemisphere and counterclockwise in the Southern Hemisphere because of the Coriolis effect. The Coriolis effect is a result of Earth's rotation.
Low barometric pressure describes an area that has lower pressure than the surrounding area. Low pressure systems often bring high winds and warm air, leading to precipitation, clouds and potentially severe storms.