mesocyclone

thumb|A mesocyclone (at left) in the Central Zone of the city of Piracicaba, in southeastern [[Brazil, on January 28, 2025]] thumb|Supercell diagram with the mesocyclone rotation in red

A mesocyclone is a meso-gamma mesoscale (or storm scale) region of rotation (vortex), typically around in diameter, most often noticed on radar within thunderstorms. In the Northern Hemisphere, it is usually located in the right rear flank (back edge with respect to direction of movement) of a supercell, or often on the eastern, or leading, flank of a high-precipitation variety of supercell. The area overlaid by a mesocyclone’s circulation may be several miles (km) wide, but substantially larger than any tornado that may develop within it, and it is within mesocyclones that intense tornadoes form.