Depending on how cold it is, it's likely just vapor. However, if it's not that cold outside then it could be (not saying it is) and internal head gasket leak. It could be slow, but enough to cause the smoke. If you've check the coolant levels and there's no appearence of a leak, keep checking it to confirm theres not a slow drain. You could also do a pressure test.
Likely nothing, but I do know mine doesn't do that in cold weather. It will upon start up but once it warms up, unless it's really cold, it subsides quckly.
I'm hoping it's nothing, not really looking forward to a head gasket job. it's just that I can still clearly see the exhaust after 20 minutes of driving, that's what has me worried.
No weird smells though.