Is a cyclone the same as a tornado?
While both tropical cyclones and tornadoes are atmospheric vortices, they have little in common. Tornadoes have diameters on the scale of hundreds of meters and are produced from a single convective storm (i.e. a thunderstorm or cumulonimbus cloud). A tropical cyclone, however, has a diameter on the scale of hundreds of kilometers and is comprised of several to dozens of convective storms. Additionally, while tornadoes require substantial vertical shear of the horizontal winds to provide ideal conditions for tornado genesis, tropical cyclones require very low values of tropospheric vertical shear in order to form and grow. Tornadoes are produced in regions of large temperature gradient, while tropical cyclones are generated in regions of near zero horizontal temperature gradient. Also, tornadoes are primarily an over-land phenomenon, as solar heating of the land surface usually contributes toward the development of the thunderstorm that spawns the vortex, although over-water tornadoes
A weather expert might tell you that a tornado is a small cyclone. To him, a cyclone is arty storm with winds spiraling into the center. It may be a tornado, a hurricane or one of the big low pressure areas that moves slowly from the west, bringing a spell of nasty weather across the land. People around the world have everyday names for storms. We call the smallest cyclone a tornado or a twister. Its furious winds twist into the center and whisk aloft. A hurricane is a much bigger storm, but its winds also spiral into the center and whisk aloft. In the north Pacific, people call the howling hurricane a typhoon, and people in Australia call it a willie willie. The weatherman calls it a tropical cyclone, because it starts in the tropics near the equator.
