Although the NAM is still a great run and comes around to my thinking for PA it still is having a tough time. See for yourself (compare 3hr forecast to radar) We still have one more hour to go for verification but I think we already see the problem :)
Model still comes in with a lot of qpf...slightly less in portions of SE PA but higher in Southern New England. But I would not worry about that as KY should be a few shades higher from the 3hr forecast.
The importance of this:
More latent heat is being release (WAY MORE) than the NAM shows from 3hrs out and the result is sinking air elsewhere. That elsewhere is to the east over the Atlantic. When that air sinks it warm. When air warms the heights rise. When the heights rise over the Atlantic it amplifies the trough over the East US.
Importance of this:
Not hard to accumulate snow with temps below freezing and at night! Already seeing areas at 30F some even lower! Most of the problems with precip type revolve around sfc temps not significant warming aloft, so very important trends need to be monitor.