Cold Front Weather

Weather along an advancing cold front is much different than that along a warm front (Figure WS.16). Friction slows the advancing cold air causing a steep slope to the front. The steep slope pushes the air ahead of it rapidly upwards and vertically developed clouds (cumulus) are produced along the front. As with a warm front, you experience a drop in the atmospheric pressure as the front approaches. As the cold front passes you, the winds shift from south to southwest, and finally to a westerly direction.

Figure WS.16 Profile of Cold Front

Figure WS.17 Towering cumulonimbus cloud 
(Source: R. Kresge, NOAA Used with permission)

With greatly contrasting air masses on either side of the front and potentially unstable conditions, violent weather can form. Towering cumulonimbus clouds are common along cold fronts producing intense downpours of rain lasting for a relatively short period of time. Tornadoes can form under the most extreme conditions ahead of an advancing cold front.

Below is a table that briefly summarizes the weather conditions associated with wave cyclones and their associated fronts. Instead of reading from left to right, read the table from right to left. Doing so will give you the perspective of the system moving through your location with its center to the north along the transect identified in Figure WS.13. Click on the cloud abbreviations to get information about them.

Weather Element	Cold Sector		Warm Sector		Cool Sector
Air Mass	cP		mT		cP
Pressure Tendency	rising		falling -- rising		falling
Wind Direction	NW - W		SW - S - SE		SE -- E
Clouds	Clring - Cu		Cb - Cu - Clring		Ns - St - As - Cs - Ci
Precipitation			Intense but short duration at cold front		Light but long duration at warm front

Cloud abbreviations:

• Ci - Cirrus

• Cs - Cirrostratus

• As - Altostratus

• St - Stratus

• Ns - Nimbostratus

• Clring - Clearing

• Cu - Cumulus

• Cb - Cumulonimbus

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