There's almost no chance the the Bills and Jets will play on Sunday in Buffalo. The area has been hit by over 5 feet of snow, and another 3 feet are on the way.
The field probably won't be ready, and it would be difficult for fans to get there. Additionally, the Bills haven't been able to practice all week. It's not realistically to expect a team to play on Sunday without having any practices.
Most likely this game will be moved to Monday or Tuesday night. That's been done many times before.
It also could be played at a different venue. An NFL source told the New York Post that the league considers Pittsburgh, Washington and Detroit to be possible contingency venues. There's also a dome nearby in Toronto, and the Bills have played games there before.
With limited practice ability, the Bills will need to go with more of a vanilla game plan. This could potentially help the Jets. On the flip side, these teams played a month, so they're already familiar with each other. The Bills won that Week 8 meeting 43-23.