A area of rotation of storm size that may often be found on the southwest part of a supercell. Its circulation can be larger than the tornado that may develop within it, but not necessarily. Originally a radar term for a rotation signature that met certain criteria, it is best seen on Doppler radar.
A
storm-scale region of rotation, typically around 2-6 miles in diameter and often found in the right rear flank of a
supercell (or often on the eastern, or front, flank of an
HP storm ). The circulation of a mesocyclone covers an area much larger than the
tornado that may develop within it. Properly used, mesocyclone is a radar term; it is defined as a rotation signature appearing on
Doppler radar that meets specific criteria for magnitude, vertical depth, and duration. Therefore, a mesocyclone should not be considered a visually-observable phenomenon (although visual evidence of rotation, such as curved
inflow bands , may imply the presence of a mesocyclone).
