There's a "pivot zone" that has been showing up on models. Some put it over NE TN (Euro, NAM 3km, WRF-ARW to an extent), some put it over the central plateau (GFS para), some put it over the Knox - Hamblen area (NAM 12km, WRF-ARW2 to an extent), some have it over NW NC (RAP). I don't know exactly how to describe it, but where ever that occurs, that's the area that gets hit the hardest.
Using the Euro to show this, just because it was easier to make and mark up gifs with it:
Here is the 500mb circulation, notice a lil lobe of vorticity kinda sort schamybe does the fujiwara dance with the main lobe:
That might be helping pull some dynamics up the eastern valley to intersect with deepish moisture:
Even at 850mb there is a little bit of vorticity that wobbles on the run over the eastern valley:
So you get this:
850 flow turns Northerly too, so Johnson City/ Elizabethton, Erwin...and... dare I say it...Flag Pond would probably keep snowing with upslope.