Why East Coasts Lack Deserts (Usually)

Rather than seeing consistent “band of deserts” in the subtropics on our planet, we actually see a major asymmetry: subtropical deserts are almost always absent from eastern coastlines. This is true in North America, South America, Australia, Southern Africa, and Australia. In general, rainfall is much greater on the eastern side of a landmass at subtropical latitudes. Why do we see this pattern? Why are eastern coastlines, at subtropical latitudes, usually much more humid? This is critical to understanding the geography of deserts.

Image Sources:
Arizona State University
Wikipedia Creative Commons (Shwollo)
Google Earth
earth.nullschool.net
NASA

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