Cold fronts result in the appearance of clouds, rain, strong winds and thunderstorms. When these conditions pass, the temperature grows cooler, dropping as much as 15 degrees Fahrenheit within an hour of the cold front's arrival.
Cold fronts happen when cold air masses displace warm air masses. Warm air is lighter than cold air, so warm air rises, and the displacement creates a disruption that dramatically alters weather conditions with thunderstorms and cooler temperatures.
Cold fronts follow specific weather patterns. For instance, the fronts move from northwest to southwest. Immediately before cold fronts pass, winds come from the south-southwest. While the cold fronts pass, winds become gusty and shift. After cold fronts leave, winds come from the west-northwest. Temperatures transition from warm to a dramatic drop to a steady drop. There are brief showers, followed by heavy rains and possible thunderstorms and an eventual clearing. Clouds progress from cirrus, cirrostratus and cumulonimbus to only cumulonimbus to cumulus.
On weather maps, cold fronts are represented by a solid blue line with triangles pointing in the direction of the cold front's movement. Temperatures on either side of the line show a dramatic difference. Generally, large temperature differences over small areas indicate the presence of cold fronts.