Pat, This two-part exercise was probably my most favorite of those I have observed from you. I am currently in Northern Indiana so not suprisingly my data looks similar to yours. The data set I used went back to the early 1890s but there was a break in data collection from about 1910-1920 (World War I?). I did not see the extreme values in precip and snow that you observe. The most extreme precip and snow values were around 200 mm and 500 mm , respectively. When looking at the ten highest snow values I found events that line up with the big snow fall in Chicago in late January 1967. The station I am using may be experiencing higher precip (snow and rain) due to the lake effect. I am not sure how far or how large the lake effect is in Michigan in your neck of the woods. Finally, I converted the snow to rain using 1:12 ratio suggested by NOAA for this region. I thought it might be interesting to compare precip and "converted from snow precip". There are some 'hint' of a trend but caution is needed since the conversion of snow to precip is highly dependent on temperature.
Hmmm. Interesting suggestion. Considering how patchy the precipitation/snow fall data are I’m not sure. Maybe for the temperature data which would be more continuous