I think using the word luck is fine. Maybe it's more like randomness. There are failure modes even when guidance looks good at say 3 days out, due to inevitable errors in timing of wave interactions, etc. There is almost always a fine line in most winter storm situations in this region(esp the cities and east), and favorable patterns for snow generally don't last that long, so 'wasting' them often amounts to 2 or 3 medium range threats that don't work out for one reason or another.