an enormous severe thunderstorm that takes on a rotation with nearly balanced updrafts and downdrafts, allowing it to persist for several hours over a large area
a powerful thunderstorm that exhibits rotation within the storm, the rotation needed to produce tornadoes
a violent storm dominated by a single gigantic cell -- a weather system made up of storm clouds and the winds associated with them
An unusually violent thunderstorm that is capable of generating tornadoes.
