Article from Wikipedia on these weather systems with winds circling a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere.

Article from Wikipedia on these low pressure weather systems with inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Article describing and explaining these atmospheric features and the kinds of weather associated with them.

Explains how air masses form, the principle classifications that influence the continental United States, and the formation of fronts between them.

Brief description of these regions of high atmospheric pressure relative to the surrounding air.