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      2-14-1984: A Three-week Thaw

      A deep, cold upper-air trough brought cold and snow to Upper Michigan on February 4, 1984.

      The temperature reached a record-breaking 43 degrees on Valentineâ??s Day 1984. This spring-like February day followed a warm storm that brought nearly an inch of rain to Iron Mountain the day before and 1.65 inches over two days to the National Weather Service (NWS) site near Negaunee.

      The winter of 1983-84 got off to a severe start with a bitter cold wave just before Christmas 1983. Six record lows were set over the week leading up to the 25th; including a bone-chilling 28 degrees below zero on December 20, 1983â??the coldest December temperature of record at the NWS. The same morning Ironwood fell to 36 below zero. January continued the cold pattern coming in 3.1 degrees below the long-term average. The first week of February was still wintry with over 20 inches of snow on the 4th and 5th, and then the pattern flipped (Images 1 and 2 above). The cold air retreated and mild Pacific air took over. Low pressure came up from the southwest, but the air, even in the cold sector of the low, was too warm for snow. The rainstorm moved out and was followed by more mild Pacific air and the record-warm Valentineâ??s Day.

      The generally mild pattern remained, though it began cooling a bit during the fourth week of the month after a remarkable 57-degree high on the 22nd. However, it still remained above average until the last day of the February 1984. The month ended a remarkable 11 degrees above average. On eight days, the high temperature reached 40 or above. Remarkably, the snow cover at the NWS shrunk from a high of 39 inches on the 6th, to 16 inches the 18th.

      Another big flip, this time to cold, occurred at the beginning of March. Some of the coldest March readings on record were observed during the first half of the month. Then a huge snowstorm came in as spring began. Over 28 inches of snow accumulated in the day storm on March 20-21, 1984.

      Our pattern has flipped to back to cold. It still appears that the coldest air will settle in from late Friday into Saturday. The southern U.P. system-snow has ended and now lake-effect is taking over. The expected north-northwest wind flow puts Ironwood to the high country of Ontonagon County as well as the Munising area under the gun for heavy accumulations on Friday into Saturday.