What is an isobar? Atmospheric pressure is the pressure of air on the Earth's surface. Wind and isobars The pressure difference is the only thing speeding wind up. If isobars are close to each other The higher the pressure difference between two areas is, the higher the wind speed is. Isobars on the Windy. Simple explanation Basic Meteorology for Yachtsmen and Yachtswomen How to read a weather map like an expert?
Subscribe to Windy. This website uses cookies to improve your experience. If you continue to browse this site, you are agreeing to our Privacy Policy and Terms of Use. An anticyclone is an area of curved isobars surrounding a high-pressure area, and the wind blows clockwise in the center of an anticyclone in the Northern Hemisphere. Open isobars forming a V-shape define a through of low pressure while high-pressured, N-shaped, open isobars define a ridge of high pressure.
These features are usually predictable, and associated with certain kinds of weather, making it easier to forecast weather for a particular area. See also Aerodynamics ; Atmosphere, composition and structure ; Atmospheric circulation ; Barometer ; Weather forecasting ; Weather mapping.
The term "isobar" originates from the Greek, isos equal and baros weight. These are formed when warm air rises over a mass of cold air. As the air lifts into regions of lower pressure, it expands, cools and condenses the water vapour as wide, flat sheets of cloud. Warm fronts are shown on synoptic charts by a solid line with semicircles pointing towards the colder air and in the direction of movement. On coloured weather maps, a warm front is drawn with a solid red line with red semicircles.
These are usually associated with depressions. A cold front is the transition zone where a cold air mass is replacing the warmer air mass. The cold air is following the warm air and gradually moves underneath the warmer air.
When the warm air is pushed upwards it will rain heavily. Often more rain will fall in the few minutes the cold front passes than it will during the whole passage of a warm front. Isobars lines of constant pressure A line drawn on a weather map connecting points of equal pressure is called an isobar.
The isobars are generated from mean sea level pressure reports and the pressure values are given in millibars. The diagram below depicts a pair of isobars.
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