It looks like the extremely warm temperatures, almost records, will last into next week. Tomorrow Chicago and New York will see highs of above 70 degrees. The normal high in New York is 57 degrees at this time of year.
The Jet Stream, which typically brings cold air down from Canada into the U.S. in the winter months, has for the last six weeks stayed much more northerly than usual. As a result, our weather has been dictated by a warmer air mass coming across the U.S. from the Pacific Ocean.