QUINCY, Ill. — Mother Nature's late winter blast has many in the Tri-States looking for spring. March is typically a month where we see a gradual warming trend, but this latest system is bringing mid-January temperatures back to the Tri-States. Old Man Winter's latest visit has many people longing for spring or wondering what happened to temperatures in the mid 40s. The Tri-States' has already see subzero temperatures this winter and the infamous polar vortex maybe in the works yet again. We must look north to understand why winter won't give up.
The Polar Vortex is an area of low pressure centered at the earth's poles. During the winter, it's typically strong, stable, and remains where's it's supposed to be cold. However, as the earth's atmosphere warms the polar vortex becomes unstable. This is when we get a shot of cold air. The center of the vortex doesn't ever make its way this far south, but it does control the Jet Stream.
During stability, the strong westerly winds high in our atmosphere, known as the Jet Stream, remains uniform. During times of instability, it wobbles and makes waves.
In the dip, or trough of the jet stream, is where cold air slides to the south. Sometimes, a part of the polar vortex gets caught up in the jet stream's flow and moves colder than average temperatures down with it. Some scientists believe this unstable polar vortex is related to the overall warming of the earth's atmosphere, but there continues to be research to better understand that correlation.