A warm front are formed when a warm mass of air is pushed into a cold air mass. Since the warm air mass at surface rises above the cold mass of air they often causes stormy weathers. Also due the difficulty of warm air in pushing the cold dense air across the surface of the earth make the warm fronts to move slower when compared to cold fronts. Unstable air produces thunderstorms around the warm fronts. solid red line with red, filled-in semicircles is used to represent a warm front on the map.
