DES MOINES, Iowa — Ready or not, a big blast of Arctic air will dive into the Midwest at the end of this week through at least the first full weekend of February.
By Sunday, the coldest air of the winter will settle in across the state.
Essentially, a piece of the polar vortex is forecast to send frigid temperatures to Iowa, including single-digit highs and subzero overnight lows.
Over the last several years, the term "polar vortex" has been used to describe any blasts of cold air in the United States, often with great fanfare and theatrics.
Here's the thing: the polar vortex is not new, and quite frankly, it is not rare.
In fact, the arrival of the polar vortex occurs just about every winter.
Put simply, the polar vortex is a center of low pressure located over the North Pole.
Like any other low-pressure system, air flows counterclockwise around the center, leading to a "vortex" of wind.
When the polar vortex is strong and stable, the jet stream keeps the most brutal cold air centered near the Arctic Circle and northern Canada.
However, when warmer air infiltrates the north and therefore weakens the polar vortex, the jet stream takes on a more amplified pattern.
Bigger dips occur in this jet stream and send unseasonably cold air farther south, often into the heart of the lower 48 states.
This type of atmospheric setup normally brings Iowa the coldest temperatures of the year.
Most recently, the polar vortex brought subzero temperatures to the Midwest in January 2019 and February 2020.
Looking ahead, it's expected we'll see similar bitter cold air towards Super Bowl Sunday and the second week of February.
By Sunday, high temperatures will be in the single digits, while overnight low temperatures will fall below zero.