Weather 101: Cold Air Damming - WECT TV6-WECT.com:News, weather & sports Wilmington, NC

Weather 101: Cold Air Damming

High pressure anchors of the northeast, funneling cooler air that gets trapped on the east side of the Appalachian Mountain chain. High pressure anchors of the northeast, funneling cooler air that gets trapped on the east side of the Appalachian Mountain chain.
The "Carolina Wedge" can lead to several days of cooler, cloudier conditions across the state and is usually the culprit to many infamous Piedmont ice storms. The "Carolina Wedge" can lead to several days of cooler, cloudier conditions across the state and is usually the culprit to many infamous Piedmont ice storms.

You may have heard our First Alert Meteorologists talk about the cold air wedge or cold air damming setup during their forecast before.

But what is it? What does it do to our weather here in southeast North Carolina? 

Typically this happens when a cold front pushes through the region ushering in cooler air across the region and an area of high pressure anchors over the New England states.

High pressure circulates clockwise and funnels cooler east and northeast winds into our area.

Winds will flow over the Labrador Current in the Atlantic Ocean (a cooler current). As the winds and cool air try to complete their circuit around the high pressure area, they are met by the Appalachian Mountains.

Cold air is more dense than warm air and doesn't like to rise as freely as warm air. The mountains act as a barrier, or a dam to keep the air from rising and results in the air spilling southward along the spine of the Appalachians into north Georgia. The cold air damming effect can be as strong to affect Alabama and eastern Mississippi as well.

A boundary usually forms either on the coast or just offshore as a delineation between the cooler air and warmer maritime air. It provides a funnel to keep the cooler air west of the boundary and warmer air east of it. 

For us in southeast North Carolina, we see an increase in clouds, occasional showers and cooler temperatures for a period of time before the boundary offshore makes moves to head inland to break things up and warm us up. 

This type of phenomena has been the culprit for many crippling ice storms in the North Carolina Piedmont as well. 

Cold air damming events can last a day or a week. It all depends on how strong the area of high pressure is to the north and the depth of the cold air. 

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