Very interesting, thanks James!

I take it that the GFS isn't warming the strat enough for it to have any real effect in our part of the atmosphere, otherwise I perhaps would have expected to see something at the 500mb level, no matter how hard I squint; nothing. ECM is no better. A split vortex should take about 10 days to propagate down. If we are generous and use the JMA that is on the 4th January, so we should see something in the troposphere by the 14th of january. So why am I seeing this?

This has to be one of the clearest NAFES mean I have ever seen at +384 hours, and it is for the exact opposite of what we want to see.

Nasty indeed, but thank goodness, it is well into fantasy island territory. I still hope to see changes coming along in the model output because of the strat warming, Shannon entropy and all that. 

Wasn't this talked about in about the first week of Dec? 

I'm not sure tbh, probably Brian or another contributor will know. 

I'm probably barking up the wrong tree again but I'm sure I remember reading that Ian F had tweeted or stated somewhere that a potential pattern change with a -NAO maybe on the way, not sure when that was suppose to kick start though, wasn't it to do with GLOSEA 5  or something.

I think it was, but from what I recall nobody here was expecting a major shift away from an atlantic dominated pattern before we reached the festive season. Most predictions I recall reading a month or so ago were for any notable cold outbreak this winter to occur sometime in January or later. The models haven't at any time this month, according to my recollection, suggested a major cold outbreak coming along before Christmas & New Year.

I'm not sure. Nonetheless, Ian's comments are probably (I'm reading them second hand so am not sure exactly what has been said) not far away from my thinking for January. Unlike a lot of the histrionic comments appearing here and elsewhere I'm not expecting it to be a particularly warm or cold month, and extremes are more likely to manifest themselves in the wind and rainfall categories with the possibility of very heavy snow over high ground in the north.

A rare piece of genuine model output discussion to be had here - NAVGEM (the only one of the three leading models which have a significant warming event around Greenland, and which has a public 18Z run) continues to suggest that the pro warming block are sticking to their guns, with the warming actually more progressive than the 12Z by 144

All the while, the two GFS models keep the warming at a lower temp level, never fully splitting the vortex to the same extent and never rising the temp above -20c (as opposed to the others which vary upto -8C or even higher).

This being the most progressive GFS run so far

One of these groups will have serious egg on faces and credibility questions with this so close for strat forecasting. Indeed, if it turns out to be a half way house then all the models have issues to answer. Genuine interest here I'd say, regardless of the effects down at our level.

First signs of a change towards end of the month!?

Well, it is widely held that ECM has the best representation of the stratosphere right the way up to 1 hPa (basically the top), followed by JMA.

Then you have quite a jump down to the likes of GFS.

This is because GFS does not model the strat all the way up to the top and as far as I know GFSP doesn't either, at least not at the moment - that's due to be added sometime later this month from what I've heard. Might be too late for the party?

So here's the deal. ECM and JMA see more of the strat. so they are almost certainly picking up on key details that GFS is missing, which means they're likely to be far closer to the mark... provided they are modelling the highest levels of the strat. accurately.

Given the strong similarity between ECM, JMA and NAVGEM (come to think of it how high up does NAVGEM model?), it seems that their modelling is all derived from the same theoretical physics and meteorology, so if they turn out to be wrong it will be a major blow to our ability to model those highest levels and there will be a lot to be learnt ASAP.

So as ITSY says, this is a genuine model issue going on right in front of us. Fascinating and to be honest rather unnerving! 

It does Stormchaser, there is a 1hpa strat paramater on the GFS and GFSP.

EDIT: You might well be right about the GFSP I can't get it to work.

I'm at a loss. How does http://www.instantweathermaps.com/ get 1hpa, is it derived from other parameters?

And this illustrates the futility of hand-picking one chart some 570 hours into the future. Any model beyond +240 in a stable pattern and considerably less in a variable set-up is practically useless IMO. Look at the verification stats: less than 0.5p at 8 days on ECM and I consider the ECM to be the better long range tool.
Add to that the fact that the CFS beyond +300 has been the Deluxe Thorntons version of all chocolate teapots lately and you can see why I chuckle when people post one snapshot of one dodgy model. Have a look on the latest CFS run - I can pretty much guarantee the chart for the same day now will look totally different.

The GFS, UKMO, ECMWF, the Bracka Fax Charts have us dominated by Low Pressure Systems one after another, with some mild sectors and SW flows but at their rear sides Cold NW Flows with risk of Night Frosts.

And it clearly looks like lasting at least 2 weeks With Main PV West to East across North Atlantic and over North NE Europe as well as Norwegian Sea as well.

The Current Stratospheric Warming looks set to develop Strongly and Affect USA ESE NW Atlantic Greenland and NE to Central and sE Europe with the UK seeing part of it as well, this should affect in Last 12 days of Jan. 2015, I find quite a Split Polar Vortex one ENE SE USA and Other for N Central Europe as stated already.

There is Unified Cross Model Agreement between ECMWF and GFS and this Winter we could well get very Cold Siberian / Arctic North and NE flow to our Weather as we go to last third of Jan. 2015 at least it will rain or snow with Snow later possible with next two weeks give Strong Gales windy and very Wet weather like last Jan. 2014-To Middle of Feb. 2014, but this winter that may be shorter length with more chance than last Jan- Feb. 2014 that we could get pretty decent frosts and winter weather and a two weeks or a few more added days this Jan. 2015 first 2 thirds be the problem with flooding risk and wind/ wave damage to happen: it will give way to different Cold weather with Snow and Frost more than boring slightly above average day night temperatures all in all a relief I am sure hoping this will be forecasted by the GFS, ECMWF and GEM, JMA and UKMO we need this and hopefully the USA winter will allow us to get on the best side that is what I want please ugh uff be good get USA up and UK down seasonal winter wise.

How about this Tally.................big changes a foot

I know and with a chance of it turning colder by the latter stages of January as forecasted by MetO etc I was trying to be optimistic and see a change in weather pattern rather than mobile zonal westerlies.

FWIW the latest ECM32 (or monthly) control run shows unrelenting zonality - 17 lows affecting the UK between now and T+768.

The "total snowfall" chart for T+768 shows the Highlands having several inches of snow, but apart from that - a small amount over Northern Ireland, most of Wales and areas north of Manchester in England. Aside from that, no snow (or sleet) whatsoever.

Here's hoping that run is as useless as CFS tends to be!

This conflicts with the OPI forewarnings and the prospect of a SSW.  Clearly there must be some mistake?

1hPa is native parameter in the GFS and GFSP. In the GFSP the name may have changed, I'd have to check. I think some of the confusion results from the integration of the strat level into GloSea 4 seasonal model in 2012. See:

http://www.bbc.co.uk/news/science-environment-19584302

As far as I'm aware it has been included in the medium range numerics for a long time which is another reason why I find some of the commentary about the strat quite surprising.

James - personally I wouldn't describe it as quite a jump down although it is widely agreed to be better. A relatively small step would be closer to the mark. If that wasn't the case more private weather agencies would find it worthwhile coughing up for the ECM data sets.

It's more likely than -10 850s...

My point is even in the most zonal of all set-ups with unrelenting westerlies and low after low pounding our shores you can find at least one random chart from some random ensemble showing a more blocked pattern. The odd decent chart should not detract from the overall story of means and clusters across the board indicating a zonal train into the near future.
The effects if any of warmings high up are not currently shown as having any effect whatsoever on surface patterns, and that is why most forecasters - including the MetO in their extended text - are not currently forecasting any significant change from what we have from now.

If something does appear, I'll be the first to comment on it

Blimey, that is a shocker