The only failure when someone posts a definitive statement before a storm happens is the poster themselves. That is a good point about what happened with that system and N Central PA scoring a coup. Punxsutawney has sn+ based on radar right now.
26/22 for an 85% relative humidity here so once snow gets over head it will start falling almost immediately. Column is almsot fully saturated. MDT is at 70% humidity themselves so not right away but would not take long.