The NAM was forecasting more mid-level frontogenesis, farther west than the GFS.
The NAM was forecasting more divergence above the frontogenesis over central New York, resulting in a stronger convergence / divergence couplet and more upward vertical motion over central New York.
The NAM was forecasting a better banding signature over central NY than the GFS, with a pronounced tongue of negative EPV become collocated with the upward branch of the frontogenetical circulation in that area.
Isentropic analysis indicated that the NAM was forecasting stronger positive pressure advection than the GFS over central New York (more isentropic up-glide).