Snowfall is a natural event. can't be predicted accurately the way we want to see the results. However December and January experience snowfall in Kedarnatha. But that doesn't mean that it snows every day during these 2 months
I think you should go for Crazy Peaks they organize the treks very well i had gone for trekking at Roopkund as well as Brahmatal which they have organised. Or else you can go for India hikes
To experience snowfall December last week to January last week would be best! check with youth hostel association of India or you can also go to sankri and take a local guide from there it would cost you around 6k
U can plan for kedarkantha in next 10-15 days or so. . .hopefully it will start snowing . beautiful place. . u can go with the Himalayan trekkers. . . .