Weather apps that report snow accumulation
Dark Sky shows expected accumulation... In my experience it is pretty inaccurate, but it tries. It has almost always forecasted more accumulation than actually accumulates. It is pretty accurate with its other predictions though.

The prediction engine that runs Dark Sky is available at http://forecast.io if you want to try it out for free. I can't remember for sure if it shows expected accumulation, but I think it does.