Cyclone

Cyclones are characterized by inward-spiraling winds that rotate about a zone of low pressure. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies.

Cyclones occur chiefly in the middle and high latitude belts of both hemispheres. In the Southern Hemisphere, where most of the terrestrial surface is covered by the oceans, cyclones are distributed in a relatively uniform manner through various longitudes. Characteristically, they form in latitudes 30° to 40° S and move in a generally southeasterly direction, reaching maturity in latitudes around 60°. The situation is quite different in the Northern Hemisphere. There, continental landmasses extend from the Equator to the Arctic, and large mountain belts interfere with the midlatitude air currents, giving rise to significant variations in the occurrence of cyclones (and anticyclones). Certain tracks are favoured by the wind systems. The principal cyclone tracks lie over the oceans, regularly traversing to the east of both mountain barriers and continental coastlines.

The structure of cyclone is usually elliptical or pear-shaped which is changed due to high wind speed. Cyclones are mainly responsible for the strong wind, heavy rain, tornadoes, and large storm at the landfall. "Cyclone" refers to their winds moving in a circle, whirling round their central clear eye, with their winds blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. The opposite direction of circulation is due to the Coriolis effect.

There are two types of cyclones:

Tropical cyclones; and.

Extra Tropical cyclones (also called Temperate cyclones or middle latitude cyclones or Frontal cyclones or Wave Cyclones).