Storms vary by basin with respect to size, intensity, track and frequency of occurrence.
The graphic above shows where these seven basins are located and typical tracks in each. It also reveals the average number of tropical storms, with winds over 39 mph, and hurricanes, with winds of 74 mph or more, spawned in each basin. Tropical cyclones often form from tropical waves , which are simply ripples or disturbances in the mean wind flow. Sometimes these are called cloud clusters because they enhance the number of tropical thundershowers in an area. Each tropical cyclone basin also has its own character.