a huge rotating thunderstorm

a long-lived storm containing a

a long-lived thunderstorm possessing within its structure a continuously rotating updraft of air

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.