The AO is a symptom and not a cause, and can oscillate from positive to negative as much as any other measured parameter.
There is plenty of cold air now pooling where it should - across the Arctic - and given suitable surface vectors this air can get pushed south of the 60deg latitude quite easily (as per Tues/Weds next week if output is to be believed).
As Martin quite rightly says it's only mid-November so expectations are reserved as far as snow fall is concerned. SSTs are only a month or so into their decline, the sun still has a bit of influence and we are in a relatively mild Autumn with fairly high soil temps.
Having said all that, it is possible to get a fall of snow widely in mid-November, but it's the exception rather than the norm.

GFS, ECM and GEM all have the look of a prolonged (more than five days) cold spell to me.

Quite agree Gavin but I feel some on here are after the holy grail which though nice would be truly exceptional this early in the season. Still there are some mouth watering synoptics around this morning and hopefully will bode well for the winter.

 I just wet myself one step at a time laddy

http://images.meteociel.fr/im/8208/cfsnh-0-408_bri8.png

Interesting synoptics this morning. Much colder and unsettled sums things up well. A cold mixture of rain, sleet and snow for most places next week now seems very likely.

A few surprises will no doubt spring up if other dynamics set themselves up in the polar flow such as shallow low pressures, troughs and evaporative cooling events etc etc.

Certainly enough to whet the appetite if wintry stuff is what you are after.

Indeed, I also wouldn't rule out some wet snow to low levels in the south from mid week onwards but nothing lasting or settling for to long if it was to happen.

That is a classic chart, no doubt about it. It is only in FI at the moment of course, but just suppose something similar comes about, it would herald a prolonged spell of proper winter for the UK and Western Europe.

If it comes to pass, what is the driver for such disruption of the Polar vortex? There has been no talk of an SSW as far as I am aware.

Hmmn. GFS version of events:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20131114/00/174/npsh500.png

PV energy taking its time clearing away from Greenland and moving to Siberia. This allows the Russian Blocking High to extend through Scandinavia and use the Mediterranean trough to gain some influence over the UK. Unfortunately there isn't any real cold to work with in that setup, as the block hasn't got troughing underneath it to advect cold surface air from the Arctic regions of the continent. It's just dank and chilly.

In FI, if the PV had dropped some energy through Scandinavia, things coud have become exciting, but the trough/block positioning prevents that on this particular run.

ECM version of events:

http://cdn.nwstatic.co.uk/ecmimages/20131114/00/npsh500.168.png

The PV energy is clearing to Siberia much more quickly, keeping that Russian High away and allowing energy to drift just to our east on day 6, rather than stalling across the UK as per GFS. At this point, ECM throws some energy NE from the Atlantic and that messes things up a bit, allowing a ridge from the SW to link up with the Russian Block. That stronger PV over Siberia does come to our aid again by day 10 though:

http://cdn.nwstatic.co.uk/ecmimages/20131114/00/npsh500.240.png

The ridge to Russia is being supressed and heights are becoming increasingly high to our NW. with the Atlantic choked of energy.

So there's a lot of potential synoptically, but IMO we're going to need a lot of luck to score something noteworthy at the surface away from high ground in England and Wales. Still, you never know...

http://expert-images.weatheronline.co.uk/daten/proficharts/en/2013/11/14/basis06/ukuk/rart/13112006_2_1406.gif

JFF JFF JFF

Distribution of Snow is different but the wintry feel is there

http://expert-images.weatheronline.co.uk/daten/proficharts/en/2013/11/14/basis06/ukuk/rart/13112200_2_1406.gif

JFF JFF JFF

Snow pushes inland

http://www.wetterzentrale.de/pics/Rtavn1861.png

http://www.wetterzentrale.de/pics/Rtavn3481.png

Deepest FI , huge block forms to the NE

That would be stunning in December with proper cold moving westwards with time.

Amazing output considering only a week ago we had the zonal express for the foreseeable.

Just goes to show how things CAN and DO change within a matter of days, despite many deciding we are 'due' a mild/ very mild winter.

However things are far from set in stone and IMO some will be disappointed next week, although the models could be picking up on more of a long term signal. Seen it happen so many times.

Totally bankrupt and full of old ruins? 

Back on the models, the 06Z GFS still has a bit of snow around for the south if not the big clump of four-flakers seen on the 0Z... http://expert-images.weatheronline.co.uk/daten/proficharts/en/2013/11/14/basis06/ukuk/rart/13112006_2_1406.gif

Hmmm. I don't remeber seeing such a consistent set of cold GFS ensembles since mid Nov 2010 (although there were better then)...

http://jp2webdesign.co.uk/TWO/ensembles/

I hope it's a precurser to a cold & snowy winter, and not an early season flash-in-the-pan that sees winter descend into a zonal crapfest.

Note to the moderators - isn't it that time of year when we setup a sticky SSW thread?

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

One thing that is irratating is the complete absense of cold uppers over the continent. We also are missing a strong scandanavian low to correct that. When that northerly peters out we are looking at cloud, fog, drizzle and snizzle at best unless we can get some colder air sourced in. 

EDIT: Look at this:

http://modeles.meteociel.fr/modeles/navgem/runs/2013111406/navgemnh-1-144.png?14-11

Despite the NAVGEM offering another nearly perfect scenario insofar as SLP goes. All the cold air has not only left Eurasia, but even the arctic itself. Its all sat on the other side of the world in Northern canada. 

^^^^^^^

It is only November Quantum.

Anyway, here's today's video update;

A Prolonged Cold Spell Setting Up?

http://www.gavsweathervids.com

We are not going to be transformed into an arctic wilderness of course, but it does look like an extended period of below average temperatures and a lot of cold rain (with a few wintry surprises) to me.

Perfect weather for Matty really!

Very true. The immediate synoptics are a tad misleading in that, ordinarily, Eastern Europe would be colder than it currently is at this time of year. So despite what look like super synotpics for cold and snow lovers, yes it would be cold and seasonal, but it wouldn't be particularly wintry as the uppers aren't quite cold enough once the initial northerly passes by and turns into the usuaully much-coveted Easterly. Ironically, we don't actually want an Easterly in the short term for snow given the above average continental temperatures. Having said all that, were the synoptics on offer to deliver a developing block to our NE, it would only be a matter of time before our train leaves the Siberian station, so it may be a short term pain long term gain setup - which given the time of year, can only be a good thing.  

Thats a lovely lovely split that really is at t144 in nh smashing chart. we cant ask for more imo.

we have plenty of time and its on our side.

http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=144&code=0&mode=0&carte=1&archive=0

For those who didn't see SM's post on Netweather, here's my take on a couple of things. Look at P7 from this morning, absolutely stunning. 

Some of the synoptics on offer are absolutely fantastic, and I hope (though don't necessarily expect) to see the amplification of high pressure to our N/NW/NE become more vertically aligned than it is now. This, as Steve alluded to on the previous page, will essentially negate the lack of cold temps over Europe at the moment by offering a direct short cut through a far more potent N/NEly type setup than on offer on many models at the moment, which deliver us with a much coveted Easterly, but which lets us down as the source (over Eastern Europe) is far warmer than normal, so the wintriness is reserved for high ground only. 

See the P7 for an illustration, absolutely stonking run for cold and snow:

http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=144&code=0&mode=0&carte=1&archive=0

This is basically, in absolute Lehmann's terms, what happened in 2010 and why we got such a severe dose of winter so early (which is also explained by Steve on the previous page). If we don't get the vertical alignment out around Southern Greenland and the Atlantic, we won't get a severe or unusually snowy cold spell for most (not all), as a Scandi high will only bring cold and seasonal weather given the warmth over Europe.

Having said all that, some scenarios on offer go on to produce a mega block over Western Russia (a result of a developing scandi high), like this:

http://www.wetterzen...s/Rtavn3481.png

If this verified, it is likely that short term frustration would develop into something far along the traditional Easterly route and bring us much colder and snowier weather across from a cooling Europe, albeit further down the line. 

But a word of caution for the newbies in particular: This is not a win-win scenario just yet, and plenty of things could happen between now and next week to scupper the development of either of these two scenarios - although make no mistake about it, if the first scenario verified, it could be something quite special. 

Ramp over. 

One of my hobbies is just how bizarre peoples views of common phrase's is. This is a gem - Are you alluding to Darren Lehmann the Aussie?

Yes the old frozen duck in november leads to a winter of muck quote will be trotted out.......oh it just did

At this time of year, the lack of cold uppers on the continent is only going to be a temporary issue. once the pfj sinks south, the colder uppers will make their way down. if we pick up a continenttal feed, uppers dont need to be too low anyway. what must be emphasised is that its still mid novebmer. look at this upcoming period as a bridge to something better later via a reload by which time we will almost be in december..