What is a warm weather front?

A warm front is where advancing warm air displaces cold air. Because the air ahead of a warm font moves more slowly than does an advancing cold air mass, the warm air encounters less friction with the ground and thus develops a gradual frontal slope rather than a steep boundary. It is characterized by extensive cloudiness and precipitation.

On a weather chart, a warm front appears as a solid red line with regularly spaced, solid red semicircles pointing in the direction of the front's motion.
Warm fronts are air masses that have warm temperatures.