1.The colder air mass is heavier than the warmer air mass, therefore the lighter, warmer air rises over the top of the heavier, colder air. When it rises, it cools. It also cools when it comes into contact with the cold air.
2.Condensation occurs and clouds form.
1.Air is forced to rise over high areas.(mountains)
2.Air cools and condenses.
3.Clouds form and it rains.
1. Sun heats the land and the air
2.Warm air rises cools and condenses, clouds form
3.Clouds let out rain.