what is a warm front?

Answer 1

When contrasting airmasses lie side by side,the narrow zone of discontinuity separating the two airmasses is called a front.
If the warmer air flows actively upwards over the cold airmass below(or a warmer airmass replaces the colder air) then it is called a warm front.As warm front approaches,temperature and dew point within the cold air gradually rise and pressure falls at an increasing rate.Precipitation usually occurs within a wide belt of some 400 Km ahead of the front.
The average slope of warm-frontal surface will be 1 to 100(or) 150.The wind will be veering in the Northern Hmisphere.The wind shift is usually 45 degrees.

Answer 2

A warm front is a mass of warm air that is pushed along by wind, usually from some form of rain storm. When it collides with a cold front, thunderstorms result.

Answer 3

A warm front is the boundary between cooler air in front of it, and warmer air behind it. Usually fronts are accompanied by rain but not always.

There is one problem with Nokel's answer, warmer air can come from the north and hit cooler air in the south. It is semi-common for a northern city to be warmer than a southern city.

Answer 4

A warm front is when hot air from southern countries collide with cold air that is drifting down from a northern country. Lets say that Mexico is giving off hot air that if trzveling north west virginia, and Canada is giving off cold air that is drifting down into west virginia. When these two temperatures collide, the air circles around in that area, then releases in differsnt direction, causing a warm front, and sometimes severe weather.