Mild Pacific air flooded the Upper Midwest in late January 1989. Temperatures were much above average across the Upper Peninsula the last week of the month. At the National Weather Service (NWS) near Negaunee, the high temperature hit a record 43 degrees on January 28, 1989. The warmth would not last. In Alaska at the same time, record cold was reported. Once the pattern shifted at the end of the month, the dam broke and bitter cold air flooded most of the United States.
At Nome in the far western portion of Alaska, the morning low was 54 below zero??the coldest ever recorded. Some locations got as low as 70 below. In the last days of January, a huge upper-air ridge built over the eastern Pacific and the cold air began draining southward. Initially, the coldest air filtered into the western U.S., but it quickly spread eastward. The high on February 1st was only 18 at the NWS. By the 4th, the low was 20 below zero. February 1989 averaged nearly six degrees below normal. Heavy lake-effect snow in the Copper Country built a snow cover of nearly five feet in some spots by late in the month. The cold continued into March and didn??t really break until the last week of the month.We are now in a mild pattern this late January, while at the same time, cold is building in Alaska and the Yukon. While not as severe as 1989, afternoon temperatures were still impressively low (Image 1 above). Some of this cold will be plunging southeastward and will bring a change to much colder later in the week.