Take an accumulation of dry cold air from the Arctic. Now you can sit down and watch the storm.
Two masses of air wedge into each other and spread out like two cars in a direct head-on collision. The long, flat collision region is called the atmospheric front.
Air movement
You remember that warm air is lighter than cold, so it rises to the top, cold air tends to fall down.
A warm front arises when a rapidly moving mass of warm air collides as if in cold air. Clouds form from the water vapor that saturates the warm air, and rain can begin.
In other cases, a mass of cold air moves faster, this mass as if frees up a place for itself, actively pushing up warmer air.
This is called a cold front, because cold air displaces warm air upward much faster than warm air rises upward itself during the formation of a warm front. What is the result? Not just cloudiness and not just rains, but all this together with violent storms, and sometimes with tornadoes.
