Cold Waves This Week and Next

By Alex Sosnowski, Expert Senior Meteorologist

January 14,2013; 8:21PM,EST

While a large part of the West got a taste of cold weather this past weekend, one blast of arctic air will roll quickly from the southern Canada Prairies to New England later this week. Another more extensive blast may follow next week.
Seasonably cold air was filtering from the southern Plains to the Northeast during the first part of this week.
Temperatures plunged below zero over part of the northern Plains this weekend, after experiencing high temperatures in the neighborhood of 40 degrees late last week.
After temperatures peaked in the 50s Saturday morning around Chicago, freezing rain was falling by late in the evening. Temperatures bottomed out into the single digits and teens in northern Illinois Monday morning.

Additional pushes of arctic air forecast to come to the Plains and Northeast are part of the result of sudden warming that took place high in the atmosphere (the stratosphere) earlier in the month near the North Pole.

The warming causes weather systems to shift around in the lower part of the atmosphere in the polar region and drive frigid air farther south. Sometimes these frigid air masses reach the mid-latitudes.

An arctic air mass later this week is moving too quickly to deliver below-zero daytime highs over northern New England, but after mild conditions from this past weekend it will have some shock value.
Temperatures could fail to rise out of the teens (Fahrenheit) in some areas of northern New England with brutal cold holding up far north in Ontario and Quebec.
The core of this air will fail to reach much of the southern mid-Atlantic. The cold air that settled over central and southern Plains will slowly moderate this week.

A zone of high pressure over the Atlantic Ocean will prevent or delay the cold air's arrival in much of the southeastern U.S.

The pattern this week is producing a series of weak storms with mostly rain, but also a swath of snow and ice on their northwestern flank.

The effect of the stratospheric warming and compensating much colder air near the surface is still evolving and will not reach its peak until late this month and on into February.