low-pressure system
Storm-making convergence of warm and cold air, circular or oblong in shape, filled with wet, windy, unstable weather; ocean-centered low-pressure systems create ground swell and are the world's primary source of high-quality waves. Low-pressure areas are formed as separate bands of cold and warm air meet and begin spiraling around each other, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. As the wind spiral rises it forms an atmospheric dome, which in tu...