Here's why:

* Warm air is less dense than cold air: This means warm air tends to rise over colder air.

* As the warm air rises, it cools and condenses: This leads to the formation of clouds and precipitation.

* The boundary between the warm and cold air is called a front: In this case, since the warm air is pushing forward, it's a warm front.

Warm fronts are associated with gradual changes in weather, often bringing light to moderate rain or snow, followed by warmer temperatures and clear skies.