A
mesocyclone is a
vortex of air within a
convective storm. It is air that rises and rotates around a vertical axis, usually in the same direction as low pressure systems in a given hemisphere. They are most often cyclonic, that is, associated with a localized
low-pressure region within a severe thunderstorm. Such
thunderstorms can feature strong surface
winds and severe
hail. Mesocyclones often occur together with
updrafts in
supercells, within which
tornadoes may form at the interchange with certain downdrafts.