Verry interesting.... I've 'talked' on and off here about a number of factors that need to be in place for another colder than average winter to occur. One of them is the north atlantic oscillation. This is essentially a weather pattern which determines the track of storms and depressions across the north atlantic ocean. When it is positive it tends to mean that the storms head over northern europe. When it is negative they tend to track over the Med. This means that we tend to get colder, drier weather in the winter. (note that drier does not necc. mean dry/snowless) (Interestingly it has a similar cold effect on the eastern coast of the US)
So, look at this series of predictions the majority of models runs showing a forecast sharp drop into a - noa. If these forecasts are correct, then it is one piece in the puzzle of a colder winter. Of course the forecast may be wrong and it may also be a short lived swing negative. We can't tell yet.