For today, the northern crew should be watching the Camp David and Westminster ASOS's. Camp David will be the first to report the changeover (they're down to 34 degrees now) which means the freezing level is dropping wholesale. If/when Westminster flips then the Pikesville/Hunt Valley crew should be about an hour behind that.
Cut the 12z euro ensemble snowfall in half and it's still a legit warning criteria event for everyone NW of I-95. That's more than all of last year before Christmas.