forced lifting by the surface of the earth

Air is also lifted by the earth itself. When air encounters a mountain range, for example, air is forced to rise up and over the mountains and if enough lifting occurs, water vapor condenses to produce orographic clouds.

In the United States, the prevailing winds are generally from west to east, so most orographic clouds form on the western side of a mountain.

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Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.