A supercell is a thunderstorm that is characterized by the presence of a mesocyclone: a deep, persistently rotating updraft.[1] For this reason, these storms are sometimes referred to as rotating thunderstorms.Supercells can occur anywhere in the world under the right pre-existing weather conditions, but they are most common in the Great Plains of the United States an area known as Tornado Alley and in the plains of Argentina, Uruguay and southern Brazil.