Depression

An area of relatively low atmospheric pressure, usually associated with cyclonic circulation and unsettled weather.

In the Northern Hemisphere the circulation is anticlockwise around the low; in the Southern Hemisphere it is clockwise. Mid-latitude depressions commonly include warm and cold fronts and can bring changing wind, rain, squalls, reduced visibility and altered sea state as they pass.

Wind strength depends more directly on the pressure gradient than on the central pressure alone. A depression is not automatically a storm, and passage planning should use its forecast track, development, fronts, gradient and local effects rather than relying on a falling barometer by itself.