Polar vortex to keep frigid pattern locked over eastern US through much of February

Waves of cold air will continue to be released across much of the eastern United States through mid-month. The ongoing pattern may tend to be stormier, with areas of snow and ice threatening to reach large areas of the Plains, Mississippi Valley, Appalachians, and Atlantic seaboard in the coming weeks.

Chilly conditions have hundreds of millions of people reaching for the thermostat and adding layers of clothing to keep warm. Persistent cold will lead to higher heating bills.

Not all winter cold patterns are due to the polar vortex. However, this storm, which usually sits near the Arctic Circle and contains the coldest air, has moved and weakened at times this winter, allowing cold air to escape south.

For many areas in the eastern half of the nation, the arctic outbreak that began in late January will continue into the first part of this week and bring some of the coldest/coldest temperatures of the winter.

“The subsequent gusts of air that occur during the first seven to 10 days of February may not be as extreme,” said AccuWeather Chief Meteorologist Paul Pastelok. “However, because continued cold has led to rapid growth of ice cover on the Great Lakes, the modifying effect of shrinking open water is progressively reduced.”

This means that there will be less warm open water to remove arctic air as it moves south, and many areas now have extensive snow cover, which further insulates the ground and helps cold air travel further and more efficiently. Both conditions also allow temperatures to drop at night when winds are light and skies are clear.

There will be a day or two here and there where the cold conditions ease a bit, thanks in part to the strengthening February sun, but any warming trend is likely to be short-lived.

“We are monitoring a possible disruption of the polar vortex in early February that may give an additional boost to the cold in the eastern US about seven to 10 days later,” Pastelok said. “Sudden warming high in the atmosphere or stratosphere tends to trigger a displacement of the polar vortex. This displacement can add more fury to a storm before the middle of the month and then more strength to the cold that follows the storm in the US.”

Frequent Arctic outbreaks in the coming weeks, or basically a continuation of what started in mid-January, will result in monthly temperatures well below the historical average for February across much of the eastern half of the United States.

Monthly temperature departures of plus or minus 2 degrees Fahrenheit are considered to be about average. Some areas may be 4, 8, 10 or even more degrees below average, especially in the Midwest, when the month ends on February 28.

AccuWeather’s long-range team not only analyzes conditions in North America, but also current conditions and anticipated changes around the globe to make their extended forecasts.

“In terms of future storms, there will be a moisture-free feature that spreads a patch of snow from portions of Missouri into Virginia Tuesday into Wednesday,” AccuWeather Senior Meteorologist Joe Lundberg said.

Another snow storm could follow a day or two later in the upper and northeast, with a second storm further south with some snow and ice to close out the week, Lundberg added.

The much larger storm that Pastelok alluded to just before the middle of the month will be closely studied in the coming days.

“That storm has the potential to bring snow and ice to much of the northern half of the country, from Montana, Wyoming and Colorado to New Jersey, New York and New England around February 12-15,” Lundberg explained.

In contrast to the frigid conditions unfolding across the eastern half to two-thirds of the nation, most areas west of the Rocky Mountains will continue with temperatures above the historical average.

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The stormy start to winter in California and the Southwest has since calmed down, but a storm in the second week of February could end that streak.

Meanwhile, people from the Plains to the Atlantic Coast should keep their snow shovels and ice scrapers handy. This harsh winter is not over yet.

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