You always here us say that the exact track of the low pressure center often dictates how much snow any location receives. Here are three scenarios:
1) The best situation for us to see a big snow in Middle Tennessee is to have the low pass to our south and southeast, through Alabama & Georgia, keeping us in the colder air and the best snow chances.
2) In our part of the country, if the low passes right over or near us, it usually warms up at first, yielding all rain until the low passes, allowing cold air to push in. Then the rain may end as snow.
3) It the low passes well to the north, it's usually all rain.
This Wednesday, it's that second scenario, the low passing right over us.
That's why we are forecasting rain until Wednesday morning when the low passes, allowing the rain to end as snow. Hence, a dusting possible for Nashville.
But to our northwest, in places like Clarksville, Ft. Campbell, Dover, Paris, & Hopkinsville, it will be closer to scenario number 1. They could see 1-2" there.
In Paducah to Evansville to Indianapolis, it will definitely be like scenario number 1. They may see 3-6"! or higher!
I also should mention the higher elevations east of Nashville from the edge of the Cumberland Plateau and eastward up onto the Plateau. They could end up seeing an inch or so due to the elevation increase.