Page:Handbook of Meteorology.djvu/63

Rh 26,000 feet. In each case the height of the Prevailing Westerlies is also the depth of the Trade Wind belt.

Winds of the United States.—The main body of the United States is situated in the belt of Prevailing Westerlies. The prevailing surface winds therefore are northwest, west, and southwest. East of the Missouri River northwest winds prevail except during the hottest part of summer when southwest winds are the rule. These include practically all the winds of various altitudes between sea level and the summit of Mount



South of the thirty-first parallel the influence of the Trade Winds is very apparent, and the prevailing winds in summer vary from northeasterly to easterly. Along the coast this influence extends much higher than the thirty-first parallel, and northeasterly fair weather winds occur at times as far north as the Maine Coast.}}

West of the Mississippi River to the Rocky Mountains, the winds vary from southwesterly to northwesterly. They are steadier and stronger than those east of the Mississippi River. Southwesterly winds prevail much of the time.