In a pattern fitting for January, waves of cold air will flow into the Midwest and East with brutal blasts of arctic air poised to sweep southeastward this week.
Following a large storm that brought snow and ice to a large part of the Upper Midwest and interior Northeast this past weekend, multiple blasts of cold air will highlight this week.
The first blast will have many people shivering as they head back to work and school in the Midwest early this week.
Another batch of arctic air set to move during the middle to second half of this week is likely to bring the lowest temperatures of the season so far to parts of the Midwest and much of New England and the mid-Atlantic.
With the frigid air moving in, temperatures may not make it out of the single digits around Chicago.
These frigid days will be followed up by even colder nights with many locations dipping well below zero. Those headed out early in the morning to work or to school should dress in layers to stay protected from the harsh cold.
It is possible temperatures fail to climb above zero F on one or more days in northern New England. Highs may be in the single digits across upstate New York and central New England with night time lows well below zero.
Highs will be in the 20s on multiple days from Boston to New York City and Philadelphia. Atlanta is likely to have highs in the 40s most days this week, despite sunshine.
Gusty winds accompanying the arctic outbreaks will produce much lower AccuWeather RealFeel® Temperatures. Because of this, the air will be beyond painful, reaching dangerous and life-threatening levels in much of the Midwest and Northeast for those who spend a significant amount of time outdoors without proper protection.
According to AccuWeather Senior Meteorologist Brett Anderson, “The pattern this week will feature a stronger influence from the northern branch of the jet stream.”
The jet stream is a fast river of air that guides weather systems along and typically separates cold air to the north from warm air to the south.
During much of December, a split in the jet stream allowed multiple storms with mild air to move across the nation.
While the new pattern will prevent storms from swinging up from the South and Gulf of Mexico with warmth and rain, it can deliver a couple of episodes of snow by way of storms from southern Canada.
The track of one such storm, an Alberta Clipper, will determine which areas receive a quick dose of accumulating snow versus just flurries from Minneapolis, Chicago and Detroit to Washington, D.C., New York City and Philadelphia during the middle of the week.
While the pattern this week will send some chilly air into the Deep South and Florida, it should not get cold enough for a damaging frost or freeze in central and South Florida.
“One thing about the pattern this week is that most days will be sunny away from the Great Lakes, when compared to the many cloudy days that December 2014 delivered,” Anderson said. “Moisture from the Gulf of Mexico will be cut off.”
The number of cloudy days far outnumbered days with partial sunshine in portions of the Midwest and Northeast during December.
As waves of cold air sweep into the North Central and Eastern states this week, warmth will build in the West.
“Rather than the pattern lock in for the remainder of the month, it looks like temperatures will again moderate at mid-month from the Central states to the East,” Anderson said.
Whether the warmup will last a couple of days or a week or more is uncertain at this time. Early indications are another shift of the polar vortex could occur at mid-month.
It is too early to say which continent in the Northern Hemisphere and correspondingly which part of North America would receive the worst of the cold air during the second half of the month.