Smoke/Moisture coming from Vents

I noticed this morning (driving longer than I normally have to) I had the A/C on and I thought I had seen some kind of smoke/moisture coming out of the vents, but when I looked I didn't see it, So I kept an eye on it, and then I saw it again...It looked like when you open your freezer and the "coldness" is coming out...I didn't smell anything, but I did turn it off...went down the road a bit more and turned the A/C back on...I didn't see anything for the first couple of minutes and then as I was going down the road, I noticed it again...I then just turned it back off. I was just using the A/C setting for top vents only, no floor vents.
Also, I have no working heater core...The heater core was bypassed whenever I bought the Jeep, So its been that way for 5 years or so with no problem.

Any idea?

Smoke/Moisture coming from Vents