SUPERCELL

A thunderstorm characterized by persistent, mesoscale rotating updraft (referred to as mesocyclones) that are deep relative to the cumulonimbus cloud top (usually 8 to 15 kilometers). Lasting as long as 6 hours, supercells may produce every type of hazardous weather: large damaging hail, frequent cloud-to-ground lightning, flash flooding, damaging outflow winds, and tornadoes. Most strong or violent tornadoes are spawned by supercells. The supercell updraft remains horizontally displaced from the downdraft so that the storm is typically longer lived than the air-mass thunderstorm. Supercells form in environments with large vertical wind shear and high instability.