Each of these basins has different large-scale influences that govern TC motion. In general, TCs move westward in the tropics and strike land or move poleward into the middle latitudes and die over land or cooler water.
Large values indicate that TCs are less predictable.
As expected, the Australian region TC forecasts are the most difficult. The northern Indian Ocean TC tracks are generally among the most predictable as their paths are usually limited to the tropics and therefore do not undergo recurvature. The TCs of the eastern North Pacific are also highly predictable due to the influence of a strong subtropical ridge which inhibits recurvature. The average number of TCs is about 25.3 per year. The majority of these occur between June and November.