When NYC is initially in the ball game oftentimes we start off cold enough for good ratios (15:1) and then transition to the crappier 9:1. The problem is the higher density snow on top can ruin your fluff a bit whereas fluff just floats on top of a dense base. You just have to think of the ratios almost as another level of ptype transition zones...i.e. fluff > normal snow > dense sugar > sleet > frz rain > rain. I find I tend to be near 0F at the sfc up here at the onset to pull off a period of fluff in a SWFE. Of course that's just my general rule of thumb...they don't all behave the same.