The dreaded phrase “polar vortex” is being used freely by the media and in day-to-day weather conversation. Temperatures that are 10 degrees below normal are not so remarkable in a typical December day in central North America. The dreaded part is that these cold-air intruders usually feature brisk winds and temperatures that do not increase much, even on a sunny day. Resulting “wind chill” conditions require caution, extra layers of clothing and “Canada Goose” coats or an equivalent.
The term “polar vortex” refers to a counter-clockwise flow of air around the North and South poles. It is a large area of low pressure and cold air surrounding both of the Earth’s poles. It almost always exists in the high Arctic and contracts in summer and strengthens in winter. During the winter season a lobe of cold air often will extend southward and sometimes detach. Some of this results in odd contrasts, i.e. Arctic temperatures much warmer than seasonal and occasionally warmer than those in southern Canada and the middle United States.
Frigid conditions that began in December 2013 were similar to many other cold outbreaks that have occurred in the past but its persistence did deserve some media hype. In North America the focus was on the polar vortex. In Europe the news was the warmest winter on record for the entire continent, especially in Scandinavia, Moscow and the eastern Arctic Ocean.
The current cold outbreak thus far has been a mere shadow of mid December 2013 and seasonal conditions are in the wings beginning early in the coming week. The holiday week presently is forecast by most agencies to be slightly warmer than average