We have always said that to get a good accumulating snow in the mid south, you need a Gulf of Mexico Low to mix with cold air.
It looks like we've got those ingredients, but it still is a tricky forecast, as usual, with Middle TN near the rain/snow line.
We think snow will be crossing the Alabama border into our southern counties by daybreak and could be in the Nashville area by mid morning.
Nashville will be on the back edge of the precipitation, and as of Tuesday evening was not included in the Winter Weather Advisory.
However, we think Nashville could see an inch, maybe two of wet snow before changing to a rain/snow mix.
To the south and east, 2-4" of snow could occur. The snow could become a mix there, as well, but in the eastern counties should end as snow.
Some models "cut off" the upper level trough accompanying the low which would allow snow to occur farther west in places like Clarksville and Waverly.