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Moisture streams in from the side of the precipitation free base and merging into a line warm uplift region where the tower of the thundercloud is tipped by the high altitude shear winds; the uplift is influenced by the Coriolis effect and the mass of clouds spins as it gains altitude up to the cap (can be up to the 55,000–70,000 feet above ground for the largest) and 'trailing' anvil. The capped moisture laden air is cooled enough to precipitate as it is rotated toward the cooler region represented by the turbulent air of the mammatus clouds where the warm air is spilling over top of the cooler invading airs. The cap is formed where shear winds (jet stream lower side) block further uplift for a time, until a relative weakness allows a breakthrough of the cap (Overshooting top); Cooler air to the right in the image may or may not form a shelf cloud, but the precipitation zone will occur where the heat engine of the uplift intermingles with the invading colder air. As the cooler but drier air circulates to the warm moisture laden inflow, the cloud base will frequently form a wall and the cloud base often experiences a 'lowering', which in extreme cases are where the tornadoes are born.
A low precipitation supercell shelf cloud. Shelf cloud forms when a cooler air mass under-flows the warmer moisture laden air.
A supercell. While many ordinary thunderstorms (squall line, single-cell, multi-cell) are similar in appearance, supercells are distinguishable by their large-scale rotation.


A supercell is a thunderstorm that is characterized by the presence of a mesocyclone: a deep, persistently rotating updraft.<ref>{{#invoke:citation/CS1|citation |CitationClass=book }}</ref> For this reason, these storms are sometimes referred to as rotating thunderstorms.<ref>ON THE MESOCYCLONE "DRY INTRUSION" AND TORNADOGENESIS. Leslie R. Lemon.</ref> Of the four classifications of thunderstorms (supercell, squall line, multi-cell, and single-cell), supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local weather up to {{safesubst:#invoke:convert|convert}} away.

Supercells are often put into three classification types: Classic, Low-precipitation (LP), and High-precipitation (HP). LP supercells are usually found in climates that are more arid, such as the high plains of the United States, and HP supercells are most often found in moist climates. 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 in an area known as Tornado Alley and in the Tornado Corridor of Argentina, Uruguay and southern Brazil.


Supercell sections
Intro  Characteristics   Geography    Anatomy of a supercell    Supercell variations    Effects    Examples   Gallery  See also  References  External links  

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