Cold Locked In for Weeks
Updated: Saturday, January 02, 2010 9:34 AM
The coldest air masses are manufactured over the frozen snowfields of the Arctic. Across that desolate territory, there is little or no effective sunlight from November through January. The snow and ice act in two ways to chill the air. First, any warmth that might exist is radiated into outer space. Second, the snow insulates the air from any ground warmth. Cold waves happen in the United States when the jet stream takes on high amplitude. This dislodges the cold from Arctic regions and forces it to plunge southward.
The current cold weather pattern will be with us through at least mid-January. It is being caused by a blocking pattern, which is simply two large pressure systems that have stalled over eastern North America. The block has and will continue to force large bodies of cold air over Canada to move southward into the United States. One very cold air mass has already arrived, and it will be followed by another even more impressive blast next week.
Patterns like this also have a habit of creating snowstorms. When and where those will happen does not become entirely evident until a few days before the event. For now, let's just say that there is a chance for a significant snowfall from the Plains to the East next week.
Story by AccuWeather.com Senior Meteorologist John Kocet.
http://www.accuweather.com/news-story.asp?partner=accuweather&traveler=0&article=7