Some of the coldest air since January will descend on the nation this week.Temperatures will plummet behind a cold front from Canada which will race fromthe northern Plains to the East Coast by the end of the week.

The coldest areas will be across the northern Plains, where temperaturesTuesday and Wednesday will reach only the single digits in some areas. For mostplaces, this will be the first time since the last week in January since thathas occurred.

As this cold air moves eastward, it will lose a little steam along the way.

Temperatures by Thursday will dip into the 20s across the Great Lakes and onlyinto the 30s across the Northeast, about 5-10 degrees below normal.

Story by AccuWeather.com Meteorologist Eric Reese.