We need to see a few below average days in the mix to have any hope to pull off a snow event. Dec 90 for example got cold right before Christmas and we ended up with a solid snow on the 27th which melted 2 days later. We just lucked out and timed it perfectly
1990 (Friday)
Today's 7.2" snowfall (which began late last night) was the first snowfall of the winter, the largest accumulation in nearly four years (since January 1987), and the biggest December snowfall since 1960. Snow ended shortly before 11 AM.