The coldest air masses are manufactured over the frozen snowfields of theArctic. Across that desolate territory, there is little or no effectivesunlight from November through January. The snow and ice act in two ways tochill 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 inthe United States when the jet stream takes on high amplitude. This dislodgesthe 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 pressuresystems that have stalled over eastern North America. The block has and willcontinue to force large bodies of cold air over Canada to move southward intothe United States. One very cold air mass has already arrived, and it will befollowed by another even more impressive blast next week.
Patterns like this also have a habit of creating snowstorms. When and wherethose will happen does not become entirely evident until a few days before theevent. For now, let's just say that there is a chance for a significantsnowfall from the Plains to the East next week.
Story by AccuWeather.com Senior Meteorologist John Kocet.
