Am I using 12/3 cable from a switch to an outlet correctly?

[leadbenny]

I'm installing a towel warmer and I thought I would include an outlet on the same cable because the towel warmer needs a junction box anyway. Can I run a 12/3 with both black/red hot, black attached to the switch, to the outlet connected to red, and continue the black to the towel warmer with all neutrals and grounds connected? It's 20 amp protected by a GFCI outlet upstream. See diagram for clarity:

 

[Megawatt]

G

I'm installing a towel warmer and I thought I would include an outlet on the same cable because the towel warmer needs a junction box anyway. Can I run a 12/3 with both black/red hot, black attached to the switch, to the outlet connected to red, and continue the black to the towel warmer with all neutrals and grounds connected? It's 20 amp protected by a GFCI outlet upstream. See diagram for clarity:
View attachment 102737

Yes you can do that but it needs to be GFCI protected so come off the load side of the GFCI receptacle for you towel warmer and receptacle