MEDIUM risk of a snow day Monday.

Lead Story: Temperatures likely cold enough for snow; alert level raised to medium.

Snow Day Alert Level: [Low] [Medium] [High] [Very High]

Discussion: A low pressure system currently located in Western Kentucky is going to move to the NNE tomorrow and bring an area of heavy snow to SE Michigan from the early afternoon on. The forecast models are likely initiating temperatures a little too warm, so most of the precipitation should fall as snow. Therefore, my snowfall map will bump totals up a little bit over what most people are saying, as the heaviest precipitation will fall at the start of this event, and therefore we could receive a good more snow than forecast if precipitation starts out as snow, or if precipitation turns over to snow more quickly than expected. I expect a quick period of rain at the start of this event, turning over to snow sooner than expected. Why? Well for one, temperatures tonight are already 1-2 degrees lower than what was forecasted. Now, I know, 1-2 degrees doesn't seem like a big difference, but it could make all the difference with this storm. See, the heaviest precipitation will fall at the start of this event, so even a changeover to snow an hour quicker than expected could result in an additional inch or two more than what was forecast. Another thing that points to possible heavier accumulations is that the precipitation is starting quicker than expected. The earlier precipitation starts tomorrow, the less time temperatures have to rebound. Therefore, I expect it to start snowing sooner than expected tomorrow, resulting in the higher accumulations than generally forecast in my snowfall map below.

So, expect precipitation to begin around noontime tomorrow. It will likely start as rain or a wintry mix, transitioning over to heavy snow sometime in the early afternoon. The snowflakes at the start of this event could be huge, and snowfall rates could easily exceed 1" per hour. Snow will then continue to fall into the evening and overnight, and this snow will continue to be heavy at times, especially if we can get some lake enhancement going overnight as winds shift to the Northeast. Wraparound snow showers will then occur on Monday as the low moves away from MI.

Now, to discuss snow day chances. Why didn't I move our alert level to high? One reason: the high bust potential with this system. Just as a quick changeover to snow will result in an additional inch or two with this system, a slow changeover will result in an inch or two less than forecasted. Therefore, I played it safe for now and kept it at medium. If the current forecast holds up tomorrow morning, I will raise our chances to high. There are a lot of things going for a snow day with this system. Firstly, this will be a long event, with snow potentially falling for 24 hours from Sunday Afternoon to Monday Afternoon. This means that the plows will have to focus on the main roads, not the back roads. Also, there will be a lot of blowing and drifting of snow, resulting in major snow drifts on the back roads that will simply be impossible for buses to move through.

The bottom line: Currently forecasted accumulations would be enough for a snow day, but I will hold off on raising our alert level to high until the bust potential minimizes for this event.

Snowfall Map: