Anticyclogenesis

Anticyclogenesis is the development or strengthening of anticyclonic, high-pressure circulation in the atmosphere, the counterpart to anticyclolysis, which weakens anticyclones, and the opposite of cyclogenesis, which develops low-pressure cyclones. It happens through downward air motion in the troposphere, forming preferentially beneath the western side of upper-level troughs, where wind and height-line patterns on weather charts converge near the level of non-divergence around 500 hectopascals. On surface weather maps a developing high is marked with an H inside its highest closed isobar, and on upper-level charts it appears within the highest closed height-line contour.