12.3.3 Frontal rain
The third rain type is known as frontal rain. It is caused by the convergence of air masses.
When a mass of warm air collides with a mass of cold air, the warm air begins to rise over the cold air. The cold air mass therefore fulfills a similar function in frontal rain as mountain ranges do in orographic rain.
When a mass of warm air collides with a mass of cold air, the warm air begins to rise over the cold air. The cold air mass therefore fulfills a similar function in frontal rain as mountain ranges do in orographic rain.