Satellite tornado

A satellite tornado is a tornado that revolves around a larger, primary tornado and interacts with the same mesocyclone. Satellite tornadoes occur apart from the primary tornado and are not considered subvortices; the primary tornado and satellite tornadoes are considered to be separate tornadoes. The cause of satellite tornadoes is not known. Such tornadoes are more often anticyclonic than are typical tornadoes and these pairs may be referred to as tornado couplets.^[1] Satellite tornadoes commonly occur in association with very powerful, large, and destructive tornadoes, indicative also of the strength and severity of the parent supercell thunderstorm.^[2]

Satellite tornadoes are relatively uncommon. When a satellite tornado does occur, there is often more than one orbiting satellite spawned during the life cycle of the tornado or with successive primary tornadoes spawned by the parent supercell (a process known as cyclic tornadogenesis and leading to a tornado family). On tornado outbreak days, if satellite tornadoes occur with one supercell, there is an elevated probability of their occurrence with other supercells.^{[citation needed]}

Satellite tornados tend to orbit their parent cyclonically, counterclockwise in the Northern Hemisphere, and clockwise in the Southern Hemisphere, and will generally form near the edge of a supercell's mesocyclone, and gradually travel inward to the parent tornado.^[3] Satellite tornadoes may merge into their companion tornado although the appearance of this occurring is often an illusion caused when an orbiting tornado revolves around the backside of a primary tornado obscuring view of the satellite.^[4] During the March 1990 Central United States tornado outbreak, one member of a tornado family (rated F5) constricted and became a satellite tornado of the next tornado of the family before merging into the new primary tornado which soon also intensified to F5.^[5]