Despite some pockets of cold air in the Midwest and East during the first part of this week, the wheels of change are already in the works for a mild weather pattern for the middle of January.
The storm departing the Northeast will briefly pull cold air into the Midwest and Eastern states into Wednesday. However, the jet stream is about to lock out the cold for the third and much of the fourth week of the month.
The jet stream is a high-speed river of air high above the ground that guides storms and air masses along across the globe.
According to Paul Pastelok, AccuWeather.com chief long-range meteorologist, "During next week, the jet stream will set up in such a way as to keep arctic air bottled up across central and northern Canada and will allow mild Pacific air to flow from west to east across much of the United States."
High temperatures may average 10 to perhaps 20 degrees Fahrenheit above normal in the northern tier states next week, compared to the 10 to 20 degree below normal temperatures during the first full week of January.
In areas from Chicago to Boston and New York City, this will translate to multiple days with highs in the 40s F. In areas from Dallas to Atlanta, the upcoming pattern will bring highs in the 60s on at least several days. From Minneapolis to Buffalo, New York, highs will reach or exceed the freezing mark during a few days.
Temperatures to Moderate This Week
The weather pattern is in transition this week.
Pockets of cold air will remain and can persist where there is snow on the ground into the middle of the week.
Clear skies and light winds at night can lead to frigid conditions during the first half of the week over the Upper Midwest to the interior Northeast.
Just enough cold air can sink southward to allow a narrow swath of ice and snow Tuesday night into Wednesday in portions of North Carolina and southern Virginia.
During the second half of the week, the pattern will feature near-normal temperatures most days in most locations from the Midwest to the Northeast and South.
When Will Arctic Air Return?
The expanding warmup forecast for next week does not mean that winter is over.
"We expect much colder air to expand southward and then eastward late in the month," Pastelok said.
"The return of the very cold air is likely to occur over the Plains and Rockies within a day or two of Jan. 24, and then the East within a couple of days of the 26th," he continued.
Snow Versus Ice, Rain Just a Matter of Timing
Through the end of January, it appears the cold air and storms will generally remain out of sync to get a major snowfall in the Interstate-95 corridor of the Northeast.
"Storm systems pushing into the Southwestern states have caused an area of high pressure to bulge northward in the Caribbean and southwest Atlantic," Pastelok said.
This has forced stronger storms to track toward the Great Lakes and weaker storms to limp off the southern Atlantic coast.
"In order for there to be be more substantial snow and ice in the coastal mid-Atlantic and southern New England, we would need cold air to come in and hold its ground as a storm is approaching, rather than give up like we have been seeing," Pastelok added.
All it would take is one or two storms to come along with just the right amount of cold air in place for locations in the mid-Atlantic and southeastern New England to receive near-average snowfall for the season.
Thus far snowfall from Washington, D.C., to New York City and Boston has averaged 25 to 50 percent of normal this winter.