I don’t believe they clear the board every time they measure. That was the old way every 6 hours.
Now, I believe it’s clear the board after 24 hours or when there is a change of precip type.
I would ignore the NAM. It does whacky things like this sometimes.
When the GFS is much colder, snowier and has support from the Rgem and others, it’s a great sign for snow lovers.