My 2013 Jetta has started making a 'rhythmic' squeaky whine that is accelerator related (gets more rhythmic as far as in and out of the whine) when the car is warmed up at highway speed. I can hear it going down the highway and stopped at a red light. It stops when I turn the A/C on. Seems to stop when I am parked and the car is put into 'park'. Any ideas?

Check the serpentine belt tensioner, idler(s) and the A/C clutch. My guess is that it is something that the belt turns.

Most likely a serpintine belt pulley has the bearing going bad. It really can't be helped with the way these cars are built. During rain and snow the cars wheels and axles toss all sorts of salt water and gunk into the serpentine belt and this causes the pulleys to go bad considerably fast. If you still have warranty tell the vw dealer about it and wait for a damp day as it will squeal more on those days.

I am voting for A/C compressor bearings as well, especially as clutch cancels it out under compressor load. 2013 Jettas are only as good as their components, so get it done soon as a warranty item.