Chicago is chilly these days, with a low predicted for Wednesday of this week of minus 21 degrees Fahrenheit. Add a 20 mile-per-hour breeze with a wind chill of minus 55 degrees and the Windy City will become the Arctic City. That’s cold, but not a record breaker as that occurred on January 29, 1985 when the mercury dropped to minus 27 degrees. I remember it well as I lived in Chicago at that time. Twitter These subzero temperatures are attributed to the “polar vortex” which is a weather phenomenon described by AccuWeather. A polar vortex is a large pocket of very cold air, typically the coldest air in the Northern Hemisphere, which sits over the polar region during the winter season. The frigid air can find its way into the United States when the polar vortex is pushed farther south, occasionally reaching southern Canada and the northern Plains, Midwest and northeastern portions of the United States. It is not clear what drives the mass of...(Read Full Article)