The direction of a typhoon's movement is generally subject to the control of large-scale air flow. The typhoons occurring in the Western North Pacific, mainly steered by the Pacific subtropical high pressure circulation, are mostly westbound in the Pacific Ocean. When they reached the vicinity of Taiwan or the Philippines which are always at the edge of the Pacific subtropical high pressure, they vary in their moving paths, with some going on westbound, some turning toward northeast, and some even lingering or moving in a circle. In general, a typhoon follows a regular path when the large-scale steering flow is clearly identifiable, and behaves more dramatically otherwise.