Definition
PRECIPITATION, often short-lived and heavy, falling from convective CLOUDS; the drops or solid particles in showers are usually bigger than the corresponding elements in other types of PRECIPITATION. Showers are characterized by their sudden beginning and ending, generally by large and rapid changes of intensity, and, most frequently, by the appearance of the sky; namely, rapid alternations of dark, menacing CLOUDS (cumulonimbus) and of CLEARANCES of short duration.