Cold front
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A cold front defined as the leading edge of a cooler and drier mass of air. The air with greater density wedges under the less dense warmer air, lifting it, which can cause the formation of a narrow line of showers and thunderstorms when enough moisture is present. This upward motion causes lowered pressure along the cold front. On weather maps, the surface position of the cold front is marked with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel. A cold front's location is at the leading edge of the temperature drop off, which in an isotherm analysis would show up as the leading edge of the isotherm gradient, and it normally lies within a sharp surface trough. Cold fronts can move up to twice as fast and produce sharper changes in weather than warm fronts. Since cold air is denser than warm air it rapidly replaces the warm air preceding the boundary. Cold fronts are usually associated with an area of low pressure, and sometimes, a warm front.
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[edit] Precipitation
A cold front commonly brings a narrow band of precipitation that follows along the leading edge of the cold front. These bands of precipitation are often very strong in nature, and especially in the Spring and Summer months, can bring severe thunderstorms and or tornadoes. In the spring, these cold fronts can be very strong, and can bring strong winds when the pressure gradient is tighter than normal. In the summer, cold fronts can cause severe thunderstorms and hailstorms, but in the winter, cold fronts sometimes come through an area with little or no precipitation, and with little or no effect on temperature. In the autumn months, cold fronts rarely bring severe thunderstorms, but are known for bringing heavy, and widespread rainstorms. These rainstorms sometimes bring flooding, and can move very slowly because cold fronts are more prone to slow movement in the fall. In the winter, cold fronts can bring severe cold spells, and heavy snowstorms. The cold fronts in the late fall become more polar in nature, and tend to bring very cold weather, and temperature drops up to 30°F.
[edit] Temperature changes
Cold fronts are the leading edge of a frigid air mass, hence the name 'cold front'. They can bring severe cold spells in the fall and winter. Very often, cold fronts are associated with deadly cold weather. Sometimes, though, cold fronts have no significant effect on the weather. When cold fronts come through, there is usually a quick, yet strong gust of wind, that shows that the cold front is passing. The effects form a cold front can last only a few hours to several weeks, depending on when the next weather front comes through.
[edit] Association with warm fronts
Cold fronts are very often associated with a warm front, squall line, or other weather front. Very commonly, cold fronts have an adjacent warm front that is ahead of the cold front. This forms an area where warm air is occurring and interacting with the cold front. In this area known as a warm sector. In the warm sector, very often severe thunderstorms, tornadoes, and hailstorms occur, because of the sharp difference between the warm air that is associated with the warm front, and the cold air that is associated with the cold front.
[edit] How cold fronts form
Cold fronts form when a cold air mass is moving into an area of warmer air. The warmer air interacts with the cold air mass, and produces precipitation.
