The weather system of the troposphere is constantly circulating like the cogs in a giant solar powered engine. The earth receives most solar energy around the equator and this causes evaporation and convection. Replacement air is drawn in from north and south and convection cells transfer the heat in jet streams away from the equator. They descend in a band of high pressure systems about 30degree N and 30 degree S of the equator. That produces warm southwesterly winds near the ground. As the heat continues to move out from the equator, the next series of convection cells are completed by updrafts and accompanying low pressure systems at latitudes of about 60 degree N and S. These are often associated heavy rains or snow.
The poles are capped by relatively stable, high pressure systems. At the same time, the rotation of the Earth produces the Coriolis force which deflects weather systems to the east in the Northern Hemisphere and to the west in the Southern Hemisphere. It is against the backdrop of this global heat engine and consequent circulatory systems that weather patterns unfold.