Senior one: cold air mass and warm air mass in front.

1. Because all these processes occur in the troposphere in the atmosphere, the temperature of the troposphere changes from cold to warm, and the warm air exchanges heat with the surrounding cold environment during the lifting process, so that the warm air mass gradually cools down.

This is warm air relative to cold air. Because high temperature contains more water vapor at the same humidity, as long as the warm air reaches the height that can form clouds and the water vapor reaches near saturation, there is a great possibility of forming clouds. But the formation of rain and snow definitely shows the existence of clouds. Because of precipitation and the formation of water droplets in clouds, ice crystals absorb water vapor and blend with the surrounding water droplets.

3. There are two kinds of cold front precipitation, because there are two kinds of cold front, which can be divided into fast moving cold front and slow moving cold front according to different speeds. The fast-moving cold front precipitation is mainly concentrated in front of Feng Yu, and the slow-moving cold front precipitation is mainly concentrated behind Feng Yu, all pointing in the direction of warm air. Warm front precipitation is concentrated in front of the front and when the front crosses the border, and the direction generally points to the direction of cold air. Their common feature is that the falling point of rain is generally consistent with the front direction.

4.c, it is to squeeze into the sky. Warm air has a low density and cold air has a high density. With the advance of cold air, the thickness of cold air is getting bigger and bigger, which makes warm air rise to high altitude.