I have been observing the CFS for several years now and find it a useful tool for getting a feel of what to expect over the coming weeks and months. During October and November if you see the CFS develop a trend for dominant mild weather during the winter months with very little if any cold showing, then the chances are high that a mild winter will occur. So far I am fairly optimistic that we will see a mixed winter fluctuating between mild and cold. The trend from the CFS over the next two months will be the most telling alongside the weather patterns during October and November for the coming winter months.
Just a side note. Durning the SSW of late December, early Jan a couple of years back when even the bbc had a special video showing bitterly cold air most likely over the coming weeks due to SSW and just about every forum foretelling of downwelling easterly winds and bitter cold for north America and Europe the CFS seemed rather non plussed about it. Yes there were a couple of cold runs but they would soon disappear and be replaced the more familiar mild runs. Sure enough the forecasted cold was being put back to the middle of January then the end of January. Finally, after being pushed back to mid February and beyond it was dropped completely.
Therefore in my view the CFS is definitely worth keeping an eye on.