While there are several characteristics of cold fronts, one of the most common is the drastic temperature differential cold fronts bring. Polar cold fronts have the potential to drop temperatures by 30 degrees Fahrenheit.
As the cold front approaches, the atmospheric pressure drops. It reaches its lowest along the front line and then suddenly increases. Observers also notice a change in the wind direction, usually from the southerly direction to the northwesterly in the United States. The approaching front brings brief showers that turn into thunderstorms as the front passes. In the wake of the front, these storms transform into showers before the weather clears.
The cold air mass often travels along the Earth's surface. At the bottom of the front, air moves much more slowly than air at higher elevations due to the effect of friction. This causes the leading edge of the front to take on a wedge shape.
Cold fronts often move quickly, up to twice the speed of a warm front. They are sometimes associated with a warm front, forming an area where the warm and cold air interact. This zone of interaction is the "warm sector" and is often associated with tornadoes. The sharp temperature differentials are responsible for the formation of hailstones.