Plain English Meaning

A storm with lightning and thunder, built around a tall, towering cloud full of fast-moving air. It carries heavy rain and rough air, and can produce hail, ice, and dangerous wind changes.

Full Definition

A localized storm produced by a cumulonimbus cloud, always accompanied by lightning and thunder, and typically containing strong updrafts and downdrafts, heavy rain, turbulence, and possible hail, icing, wind shear, or tornadoes. A thunderstorm forms when three conditions are present together: sufficient moisture, an unstable atmosphere ( air below, cooler air above), and a to the air rising.