[AndrewCologne]

For the northeast I would never use 20w50, 15w50 or even 10w60. In those cold NE winter areas at deep cold temps the oil would take much longer to reach the important parts for lubrification.
Just look into the TDS from the manufacturers and compare the viscosity value at low temps with values from oils like 5w40, 10w40 or 15w40.

You can easely change to a non synthetic one. The other way around is (if its really the case as IMHO its a rumor) more problematic. You have no benefit when using synthetic oil for simple street use. Just change your oil every year, check the CO for proper mixture and everything will be fine.