Lets see what the 12z bring, often it backtracks slightly on the 6z (I hope not this time), rolling soon should be interesting... 

Pretty similar evolution out to t144

Similar, but also - less activity to the north.  Previous run had lots of toughs to the north, this run there are less... that can sometimes point to a switch to a height rise around there are some point.

Something tells me that cold air to the east still has some play in it yet.

Still - that GH still looking ok out to the west,

North west scotland looks to be in for a pasting snow wise into early next week.

Temps down to the minus double digits across he snow fields.

edit:  also - that GH is begginning to look like an absolute monster.

Pretty decent GFS so far, the key of course is the robustness of blocking out in the Atlantic, runners cannot get between the Atlantic High and Greenland heights or they are through the corridor of death and it's hello Mr Toppler.

agreed, and this doesn't make the picture any clearer: 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

At least we should have clarity on the pattern change by the end of this week.

GH breaks down as LP tries to topple... or is it'? another plunge is spotted from the north

This has the hall marks of a northerly needing 3 or 4 goes to get going...seen it a few times.

GFS 12z looks like the ECM.. toppler, the most likely outcome IMO. 

Spot the difference, GFS 12z vs ECM 00z day 10

GFS12z goes for a fairly short and not very potent cold shot which then topples.

Yeah it's a long way out, and there are differences in the charts, but having two models even showing that kind of set up at 10 days is worth noting.

.... Leading to higher heights in Europe and a potentially locked zonal flow. A lot to play for, but this does have all the hall marks of a 48 hour toppler 

So, that's all sorted then a "2 day toppler" followed by zonal weather for the rest of the winter.

So much certainty of every outcome, every day despite the fact that the outcomes are different on each consecutive day. If I didn't know better I would say some people are on the wind up.

Anyway back on topic and at a glance the mid-term 12z GFS ensemble data looks colder than the previous suite.

All this talk of bloody topplers!

Do some people actually know what a toppler is

Let me in lighten you, a toppler is normally a ridge that topples from NW to SE into Europe allowing milder SW'lelys in.

The GFS 12z does not show that nor does the ECM 00z.

Where did you read the textbook definition of a toppler?

The GFS control is a good run very cold by day 10.

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=240&mode=0&carte=0

Yes at this stage you would have to back that outcome, but there is a good deal of uncertainty over the upstream pattern and how the GFS gets there with that stalled trough South of Iceland, looks unlikely.

Yes, some of the GEFS12z perturbations will offer quite a lot of encouragement today for cold weather fans.

Its my definition from the years I've spent on here Brian.

But learning from the like of Bren, MVH (Matt) etc.

I can't recall anyone using the term on TWO before I did but I could be wrong.