Storms are generally associated with low-pressure zones. In other words, a cyclone is a region at a given level in the atmosphere where the barometric pressure is lower than in the surrounding regions. Cyclones are associated with clouds and precipitation. Other features are high temperature and humidity gradients, as well as pronounced changes in the type of cloud cover. The winds in these cyclonic systems blow in a counterclockwise direction in the northern hemisphere, and clockwise in the southern hemisphere.
Anticyclones are systems in which the winds turn around a region of high pressure.
They are systems in which the air turns in a clockwise direction in the northern hemisphere, and counterclockwise in the southern hemisphere. Their formation is caused by air which descends toward areas of low pressure. Anticyclones are associated with fair weather and clear, cloudless skies, and are characterized by stable air. The descending air from these systems prevents moisture from rising into the atmosphere and forming clouds. In reality, therefore, winds do not blow directly from an area of high pressure to one of low pressure as theory would have it, but are deflected by the Coriolis effect.