I think that our collective reasoning, on model-predicted snow-chances, has evolved?
Back in 2003, it seemed that the 528 dam line was the Holy Grail; but no more: IMO (taking variables like distance from the coast, RH values, even wind speed, into consideration) an 850 temp of -8 to -10C is the thing to look for? In Jan, 2010, Inverness had sleet with 850s of -9C??