The big question: will we see a White Christmas?
•Any snow on the ground on December 25th
•Any snow falling on December 25th
•At least 1" of snow falling on December 25th
Clearly the whole White Christmas thing is a bit murkier than you'd probably think. For the purpose of keeping things simple, we will use the official definition used by the NWS.What about the historical probability of a White Christmas in nearby cities? Well, chances drop substantially as you head south and away from lake effect zones. For example, Fort Wayne sees a White Christmas 35% of the time. Chicago gets one 41% of the time. How will these averages stack up to this year's forecast? As of December 13th, the chances are slightly lower than average. Locations north of I-70 have at least a chance as it looks now. Areas down-wind of the Great Lakes and north into Minnesota, Wisconsin and Michigan have an even better chance. Really, the only areas with a very high chance of a White Christmas are far northern Minnesota and the Upper Peninsula of Michigan. Unfortunately for snow-lovers, the pattern is quite unfavorable for snow through roughly December 22nd or so. After that, a substantial pattern change is likely for the Great Lakes and Midwest. That is why there is at least a chance for a White Christmas north of Interstate 70. We could have enough cold air in place from the 22nd to Christmas Day to support some snow. For South Bend and much of Michiana, the chances are running just under 40% for at least 1" of snow to be on the ground at some point on Christmas. This is obviously subject to change as we get closer, but there is a chance. Keep in mind that it's certainly possible that we could have snow on the ground on Christmas, but not the one-inch requirement to be deemed a White Christmas. The chances for less than 1" of snow to be on the ground on Christmas morning are definitely higher. It's also a possibility that snowflakes could be flying on Christmas Day without any snow actually on the ground. Again, this is not technically a White Christmas, but it will make things look pretty!