It pains me to type this out, but.....
Going back to 1880, there isn't much in the way of May snow at Detroit. Out of the 140 May's, only 8 have recorded at least 0.1" of snow. The most recent instance of accumulating snow in May in Detroit was 0.1" on 5/3/2005. The other May's that had accumulating snow were 1954 (0.1"), 1923 (6.0"), 1912 (1.5"), 1909 (0.4"), 1907 (0.2"), 1902 (0.5"), and 1883 (5.0"). May 1923's 6.0" all came from one storm on the 9th. May 1883's 5.0" incredibly came on the 21st into the 22nd. The rest of those months had 1.5" or less. Will DTW get accumulating snow this month? It's certainly possible with this pattern. If the airport does, then it would put this month into some very rare air.
F this upcoming pattern though. It was beautiful this weekend.