Noun
English Wikipedia has an article on:mesocycloneWikipedia
mesocyclone (plural mesocyclones)
An area of vertical atmospheric rotation in supercell thunderstorms, which signals the threat of a possible tornado.
As the first mesocyclone and associated tornado dissipate, the storm's inflow may be concentrated into a new area closer to the center of the storm and possibly feed a new mesocyclone. Source: Internet
As the tornado enters the dissipating stage, its associated mesocyclone often weakens as well, as the rear flank downdraft cuts off the inflow powering it. Source: Internet
Formation As the mesocyclone lowers below the cloud base, it begins to take in cool, moist air from the downdraft region of the storm. Source: Internet
Occasionally, the old (occluded) mesocyclone and the new mesocyclone produce a tornado at the same time. Source: Internet
If a new mesocyclone develops, the cycle may start again, producing one or more new tornadoes. Source: Internet
Rotating wall clouds may be a visual manifestation of a low-level mesocyclone. Source: Internet