Polar Vortex

Context: Polar Vortex threatens to send US, Europe into deep freeze

• High in the atmosphere above the North Pole, a spike in temperatures may soon send bone-rattling chills spilling down through the Northern Hemisphere.
• The icy blasts threatening to sweep across North America, Europe and Asia starting in late January are from the same weather pattern that triggered the 2014 cold snap known as the polar vortex.
• It's common during winter for frigid air to roar down from the Arctic.
• But the cold mostly stayed bottled up around the North Pole in the season of 2019-2020.

Polar vortex

• The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles.
• It always exists near the poles, but weakens in summer and strengthens in winter.
• The term "vortex" refers to the counter-clockwise flow of air that helps keep the colder air near the Poles.
• Many times during winter in the northern hemisphere, the polar vortex will expand, sending cold air southward with the jet stream
• It rotates counter-clockwise at the North Pole and clockwise at the South Pole, i.e., both polar vortices rotate eastward around the poles.
• The vortices weaken and strengthen from year to year.
• As with other cyclones, their rotation is driven by the Coriolis effect.
• Ozone depletion occurs within the polar vortices – particularly over the Southern Hemisphere – reaching a maximum depletion in the spring.
• Polar vortices are weakest during summer and strongest during winter.

https://www.ndtv.com/world-news/polar-vortex-threatens-to-send-us-europe-into-deep-freeze-2350559