Yup. For years. It is on point at sniffing out that warm nose at mid levels. I have no idea what the percentage is? But, I would say it's 90% correct most of the time.
If as you say there's alot of subsidence to the north and south of the heaviest snow band. Why would you say you could see ALOT of sleet south of that band? That would not be subsidence??
Imagine the chaotic forecast the NWS would have if they just used Modelology, and not Meteorology. Changing their forecast every couple hrs, when a new model run comes out. It would be ridiculous, and no one would pay them any mind.