Movement of cyclones
Movement of Cyclones steered by the global winds
The global wind pattern is also known as the "general circulation" and the surface winds of each hemisphere are divided into three wind belts:
Polar Easterlies: From 60-90 degrees latitude.
Prevailing Westerlies: From 30-60 degrees latitude (aka Westerlies).
Tropical Easterlies: From 0-30 degrees latitude (aka Trade Winds).
The
easterly trade winds of both hemispheres converge at
an area near the equator called the "Intertropical
Convergence Zone (ITCZ)", producing a narrow band
of clouds and thunderstorms that encircle portions of
the globe.
The path of a cyclone greatly depends upon the wind belt in which it is located. A cyclone originating in the eastern tropical Pacific, for example, is driven westward by easterly trade winds in the tropics.
Eventually, these storms turn northwestward around the subtropical high and migrate into higher latitudes.
In
time, cyclones move into the middle latitudes and are
driven northeastward by the westerlies, occasionally
merging with midlatitude frontal systems.
Cyclones draw their energy from the warm surface water of the tropics and latent heat of condensation, which explains why cyclones dissipate rapidly once they move over cold water.
