We are in for quite a dramatic shift to colder starting on Thursday. Then it looks like a chilly period well into next week. I say chilly, but not necessarily cold; certainly not the winter cold experienced in Upper Michigan 31 years ago.
A deep upper-air trough developed over the Great Lakes in the days preceding this arctic blast (Image 1 above). Cold air brought in by this trough led to lake-effect snow. There had to be a snow cover in Ironwood to get down to 5 above zero on the morning of October 24, 1981??easily the coldest temperature there so early in the season. Even the Houghton County Airport with the warming influence of Lake Superior to its east and west hit 17. Other lows included 17 at Iron Mountain, 16 at Marquette and a record early-season low of 13 degrees at Munising.
October 1981 ended a chilly 4.5 degrees below average. However, the cold did not hold into the eleventh month; in fact, it already began to warm at the end of October. November 1981 wound up over 5 degrees above average. I have mentioned a number of times how a warm November correlates strongly to a milder-than-average following winter in Upper Michigan. There are a few exceptions and the winter of 1981-82 was one of them. It began cooling in December and January 1982 turned out to be one of the coldest months on record.