One of the wettest periods on record in Upper Michigan culminated in a snowstorm over many sections on May 6-7, 1960. Old timers in Negaunee and Ishpeming were unable to remember worse weather the first week of May. May Day was preceded by a sloppy four to eight inches of snow over central sections on April 30. After a brief dry spell, new low pressure formed from the Rockies into the High Plains on May 3, while a frontal boundary set up from the low into the Upper Great Lakes, paralleling the developing southwest flow aloft. Waves of low pressure rippled along the stalled boundary, drawing abundant moisture northward, producing more unwanted rain over the waterlogged U.P. May 4-5.
Finally, the main storm lifted northeastward out of the Texas Panhandle, drawing in cold air from an extensive pool of chill trapped over central Canada by persistent high-latitude blocking to the north. The low lifted slowly northeastward to Wisconsin then the Lower Peninsula while deepening, providing a perfect set-up for heavy snow over Upper Michigan on May 6-7. .
Snow amounts from this storm were worthy of a mid-winter snowfall. Marquette only tallied 8.8 inches because a good share of the precipitation mixed with rain. The higher elevations west of town had mostly snow. Ishpeming reported 14 inches with three-to-four-foot drifts. The high temperature there on Saturday, May 6 only made 32 degrees and on Sunday 33. The Marquette County Airport in Negaunee Township was buried under nearly two feet of wet, heavy snow. â??Extremely dangerousâ?? driving was reported down south in Dickinson County and up north the May chill allowed Houghton to retain a 3 inch snow cover on May 9, two days after the unseasonable storm.
It took 30 years before another storm of this magnitude hit the U.P. so late in the season. The big storm of May 9-10, 1990 followed unseasonably warm weather during late April and early May.No big storm is expected, but after a mild week with some cooling late, a major trough is forecast to dig into the Upper Lakes to begin the weekend (Image 3). This cold system will probably bring at least some snow showers and flurries to parts of the U.P. this weekend.