Chain reaction could unleash cold polar vortex across United States through April

Winter isn't over just yet. A major shift in the weather pattern could have millions across the United States once again reaching for their winter coats later this month before milder springlike air arrives for good.

The polar vortex is a part of Earth's atmosphere that is found over the North Pole. Strong winds typically keep the vortex locked in place, but periodically, changes in the weather can cause the vortex to wobble and even separate into pieces, which results in waves of frigid Arctic air being ushered southward across North America, Europe and Asia.

Not every cold snap is connected to the polar vortex, but when it does go on the move, it can result in some of the lowest temperatures of the winter season.

Like falling dominoes, one change in the weather in a part of the world will have big ramifications thousands of miles away.

A "sudden stratospheric warming event" into next week will weaken the winds that confine the polar vortex to around the North Pole. As a result, it is expected to shift away from its polar residency, eventually sending cold air from the Arctic into North America and Eurasia.

AccuWeather Long-range Expert Paul Pastelok said the shifting and stretching of the polar vortex could affect the United States around the middle of March with effects potentially lingering into early April.

Last autumn, AccuWeather highlighted the transition from winter to spring as the period when the polar vortex could pay a visit to the U.S.

With plenty of cold air in place, the colder pattern during the second half of March could set the stage for springtime snowstorms.

Pastelok said there are signs that a major storm could unfold across the central and eastern U.S. around St. Patrick's Day weekend. This could be "the beginning of a rough and stormy pattern for eastern North America through the rest of March into early April."

Even if this storm does not come to fruition, a prolonged period of colder weather could result in higher heating and electric bills on the heels of a winter that was colder and snowier than others in recent years.

Additionally, Pastelok said that the upcoming pattern could limit the severe weather potential from the upper Midwest, Great Lakes, Ohio Valley on east.