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MILWAUKEE - Polar Vortex is making its swirl around on social media again—let's talk about it!
What is the polar vortex?
Digging into the science:
It is a large area of low-pressure and cold air surrounding both of Earth’s poles. It always exists but weakens in the summer and strengthens in the winter. The term "vortex" refers to the counterclockwise flow of air that keeps it cool near the poles. The polar vortex is not at the Earth’s surface—but rather 10 to 30 miles above Earth in the stratosphere. However, cold arctic air can surge down to the surface, which is why we feel cold conditions when it impacts us.
During the winter in the Northern Hemisphere, the polar vortex weakens at times, due to sudden stratospheric warming, sending cold air southward with the jet stream. The warming in the stratosphere is not caused by warm air near the surface of Earth rising in the sky, but rather the weakened jet has sinking air at the poles which compresses and warms from above. Things such as El Niño can have an impact on the Polar Vortex too.
This causes the polar vortex to become weaker, leading to impacts lower in the atmosphere by making the jet stream wavier and slower. This ca...