My daughter is a meteorology major at a large university, and she explained that forecasting snow totals is very very difficult. It requires complicated calculus calculations at each level of the atmosphere. They really do the best they can.
I know! My wx is determined by the “Allegheny Plateau” which either BLOCKS snow systems or ENHANCES them. Up until last night, we were to get 1-3 TOTAL. The system pushed further north and we got blasted here. But about 35 miles from my house, relatives who live in the “North Hills” of Pittsburgh had about an inch. The cut off line was that distinct.