Mountain forecasting is hard, no matter where you are. The models generally don't account for upslope and local terrain effects well, and often underestimate precip and snow. I have spent a lot of time in mountains from Virginia to Maine and from Colorado to the Cascades, and the NWS zone forecasts are never very good.
That said, NWS PIT handled this event well - they issued a WSW for Tucker yesterday for 5-9" and were right on the mark.
Most people here probably know about it, but for those who don't, http://data.canaanmtnsnow.com/ is a great local resource for Davis/Canaan.