The ECMWF Ensemble Control is a member of the ECMWF Ensemble Prediction System (EPS), which is comprised of 52 separate ECMWF model runs, each of which has been changed a little one way or another to create a big ensemble that is currently considered the most prestigious in the world. One of those 52 members is the ensemble Control, which is called a control member because it has not been deliberately changed like the other ensemble members.
The pattern that will be setting up in 10 days (close to the forecasted image above, which is valid for next Wednesday) does look rather supportive of a cold weather pattern in the United States. I have yet to dig deeper into just how favorable the pattern will be, and I plan to do so sometime on New Years Eve or New Years Day. Until then, just keep in mind that this cold pattern is here to stay. Maybe not as intense as what is shown above, but it will be cold.