Explanation:

• The wind circulation at the earth's surface around low and high pressure regions on many occasions is closely related to the wind circulation at higher level. Generally, over low pressure area the air will converge and rise. Over high pressure area the air will subside from above and diverge at the surface. Apart from convergence, some eddies, convection currents, orographic uplift and uplift along fronts cause the rising of air, which is essential for the formation of clouds and precipitation.
• An eddy is a circulation that develops when the winds flows over or adjacent to a rough terrain, building, mountain or other obstruction. It usually forms over the lee (downwind or sheltered) side of the obstruction. Eddies may have horizontal or vertical circulations that can be either cyclonic or anticyclonic.