Been loking at he CFS runs as they come out and it really is struggling ot produce anything wintry for a decent period through the months of DJF
JFF JFF JFF JFF
Originally Posted by: Stormchaser
Well it is a model that has a case of over-progressiveness that makes GFS FI look sensible and restrained 
I have long wondered how it ever manages to produce multi-run averages indicating high latitude blocking, and from what I've seen over the past year, it appears that even when it sends the jet well to the south south, it keeps it very active, producing vicious storms which in turn support monstrous blocking highs that span huge stretches of the northern hemisphere.
That's why when it does show a bit of high-lat. blocking, it tends to be sensational, leading to those charts that leave people dreaming of raging blizzards and all the rest.
What's more, CFS loves to project a very flat jet profile (fits with the tendency to ramp up the intensity), so on those occasions where that jet is fired due east, CFS can end up showing an entire month of blizzard after blizzard
. Conversely, if the jet is fired NE, the blocking lasts no more than a few days.
Thanks to the habit of developing huge storm systems, CFS favours the NE jet, which IMO makes those occasions when it shows more than a transient period of blocking a more significant occurance; it's working against even greater odds than reality to project that.
I have given this a lot of thought over the past 12 months. The tendency to develop extensive blocking only occasionally, but to then take that to the extreme, explains a lot of what I've observed, but what about others on this forum? I'm very interested in your opinions on this 
Originally Posted by: Gooner