Weather Talk: Supercell thunderstorms often become severe
You may have heard the term supercell in reference to thunderstorms without really knowing what it means. A supercell thunderstorm is characterized by the presence of a mesocyclone (a strong, persistently rotating updraft).
Supercell thunderstorms are usually isolated from other storms and, more often than not, become severe. The presence of a strong updraft leads to the development of hail. The hail size depends on the strength of the updraft.
Not only do these storms have an updraft but they have a downdraft, so damaging wind gusts can be produced in the outflow from the storm. Aside from large hail and wind, these types of storms also produce tornadoes. Since the storm already has strong rotation within the mesocyclone, sometimes a smaller, secondary rotation forms and reaches down to the ground.
Supercells are most common in the Great Plains but can occur in most parts of the world. The interesting thing with these types of thunderstorms is that they are self-sustaining, so they can last for several hours.