violent atmospheric disturbance, characterized by low barometric pressure, cloud cover, precipitation, strong winds, and possibly lightning and thunder.

Storm is a generic term, popularly used to describe a large variety of atmospheric disturbances, ranging from ordinary rain showers and snowstorms to thunderstorms, wind and wind-related disturbances, such as gales, tornadoes, tropical cyclones, and sandstorms.

In meteorological terminology storm is restricted to a cyclone with a strong low pressure centre, strong winds, ranging from 103–117 kilometres per hour (64–73 miles per hour), accompanied by heavy precipitation, and at times, lightning and thunder. For specific types of storms, see thunderstorm; tornado; tropical cyclone.