How is a cold air mass similar to a mountain range as to the affect on a warm air mass

The similarity can be seen in that that the cold air masses are low, more dense, heavier air masses, the same goes for the air masses from the mountains. The cold air masses are usually appearing at night, the same goes for the air masses from the mountains. The colder air masses push the warm air masses and take their place, similar the air masses from the mountains push the warm air from bellow to go up, and take it's place.