TPMS Question and cold weather

Hi guys I got an 2014 SE back in Sept with factory 20" wheels.
I know when it gets cold tires can loose pressure and you should measure them while they're cold.

What tire pressure should I run the factory 20" wheels?
Tonight my TPMS sensor came on. It flashed a few times and then went solid.
I looked at the message center and it said"Service Required Tire Pressure System"
I then looked at the tire pressure screen at the time the pressure was FR31,FL32,RL30,RR34. The RL dropped to 29 for a second but by the time I got done driving it had moved to 31. So both Left tires said 31 and the right front was 32, rear 34 when I parked.

The temp outside is about 25* and looking for snow tomorrow. I'm in TN so it doesn't get too bad on this end of the state normally. I'm off so I'm not leaving the house.

If I put air in the tires and drive will the light turn off or am I going to have to take this thing to a dealer?

Again what PSI should I pump them to? First car I've had with TPMS sensors.

Thanks
Daps