By Alex Sosnowski, Expert Senior Meteorologist
January 04, 2013
Beginning near or just past the middle of the month, signs are pointing toward waves of frigid air moving southward across North America from the North Pole.
Much of the nation has been experiencing higher-than-average temperatures and lower heating bills so far during the cold weather season, with the exception of some bouts the past couple of weeks.
However, there are signs of a potential change on the way beginning during the second half of January.
A phenomenon known as sudden stratospheric warming has occurred in the arctic region during the past few days. The stratosphere is located between 6 miles and 30 miles above the ground.
Often when this occurs, it forces cold air to build in the lowest layer of the atmosphere then to drive southward.
The problem is the exact timing and location of the emergence of this cold air is uncertain. Typically, the movement of cold air begins 10 to 14 days later.
During the next week or so, a flow of milder Pacific air will invade much of the nation. Because of the time of year, some locations (the northern part of the Great Basin and northern New England) may hold on to the cold they have now due to long nights, light winds and weak sunshine. However, most locations will experience an upswing in temperature for at least a several-day period.