Question

What happens to warm, moist air which rises up the western side of a mountain?

Answer 1

It turns into vapor then takes form into a cloud and makes rain, or snow if its cold enough.

Answer 2

If warm moist air rises, it will expand and cool. As it cools, the relative humidity will increase and water will condense. It can then fall back to the earth as precipitation. As air rises, it expands because there is less atmospheric pressure at higher altitudes