A dangerously cold Arctic blast is poised to blanket the tri-state area.  Get your warmest coats, hats, mittens and scarves ready, because Friday, and again next week, we’ll be dealing with extreme cold. Wind gusts over 30 miles per hour Thursday afternoon and evening mark the onset of the temperature tumble and make wind chill values drop to the teens in the New York City metro area by Thursday evening. Fortunately, the wind will die down by Friday morning, when temperatures are coldest but even a light wind will keep the wind chill in the single digits to teens in most of the tri-state. By Friday afternoon, temperatures will rebound only slightly, with wind chills holding in the 20s in most places. The weekend will bring us warmer temperatures, but highs will still be well below the upper 40s that are normal for this time of year. And the “warm-up” will be short-lived, because another dose of arctic air plunges our way Monday and Tuesday.  By Tuesday morning, actual air temperatures – not including the wind – will be in the teens for most of us. The culprit for our unusually cold start to the winter season is the polar vortex – a tight, spinning pocket of cold air at the North Pole. When the polar vortex is strong, the frigid Arctic air stays locked up near the pole.  Recently, however, the polar vortex has been weak, which weakens the polar jet stream and makes it wobbly.  That allows for the jet to drop south, which sends pockets of Arctic air into the lower latitudes – including the tri-state area. Our cold pattern will stay in place for the foreseeable future.  The two-week outlook keeps the northeast colder than normal, while the western U.S. enjoys balmy temperatures. ...read more read less