I continue to post here from time to time, and yes I am still at NWS Mount Holly. The PHL measurement has not been taken in National Park, NJ in years. It is done at the airport. Airport’s are not the best places to measure snow but they do their best.
As for snow ratios, we have in-house tools where we can blend different models to get the values desired. WPC also provides guidance on the ratios. Lots of internal collaboration occurs especially with big events like yesterday. We then use tools that take the forecast QPF and apply the selected ratios to give snowfall amounts. This can also account for temperatures as well. So in short, our forecast snowfall does account for ratios.