Theories abound when a SSW is forecast to occur as to whether it will be a displacement or split, will it downwell or not and if yes how long will it take. Also where will see the cold and where will see the warmth unfortunately NO ONE knows the answer to these questions. It is only by looking at past events plus following NWP models and strat forecast models that a clearer picture develops. Many boffins come out of the wood work professing to know what lays ahead but in truth they are as unsure as the rest of us. Hopefully the picture will become clearer over the coming days.

its my annual Christmas pub crawl on 7th, early this year. Could really do with something seasonal as the past God knows how many Decembers have been wet, dull and miserable down here.

Well, that's quite clearly not the case as even a perfunctory glance at the ensembles would confirm.

ECM 12z ensemble for London

http://www.weathercast.co.uk/meteo/eps/ensemble-tt6-london.gif

Still a lot of uncertainty beyond Day 6 but the cold cluster remains - for the third successive run.

  In GFS, the current LP moves off S-wards on Sat, then LP over the Atlantic moving NE to Norway for the following week, deepest and closest on Thu 28th - that's a repeat of yesterday, though the LP is a bit more reluctant to depart. But new for the whole week of the 2nd, a narrow ridge of HP is sandwiched over the UK between Atlantic southerlies and continental northerlies - would only take slight  movement of LP on either side for this to disappear.

ECM prefers to continue to run shallow depressions across the UK, though there is a suggestion at the end of its run (the 1st) that it may also discover that ridge of HP

No general conclusions from ens runs, you'll need to look them up for your area, but nowhere stays really dry for long, contradicting GFS above.

I'll get excited about SSW when I see it, it doesn't blow my dog whistle.

Yes - you have to laugh how it's bitterly cold to our west over eastern Seaboard/ Canada and N. Atlantic and (just)to our east on other side of North sea over Scandinavia and continental and the UK is going pizza express slice! Hate to use this term but it's true:

Only one run - but does show cold air arriving end of November. - just doesn't know where. I wonder what the 06z run shiows.

The Pizza Slice is back and its a very valid description I must admit

This low 'zipper low' is appearing regularly and can be seen in many of the ensembles.

www.wetterzentrale.de/maps/GFSP12EU06_0_2.png

Its one to watch - I suspect its track and development could be pivitol on the outcome in the next week or so.

I have to say looking through the 06z a number of things stand out:

- We are heading into a very volatile period, with rapid low pressure development. Temperature contrasts look big.

- Signal for progressively colder N/NW outbreaks and some slider lows.

- Key time point remains around the 29 November

Summary

Some places are going to be very wet or very white. An exciting few weeks ahead.

For me we are heading for a set-up of High pressure close to the South for early December, especially if the synoptics of heights over Greenland failing to block the Atlantic plays out before that.

Cut and paste.

A more neutral view would be one of typical uncertainty and the ENS spread alone suggests your forecast is one of many options.

The one thng I'm seeing in response to the upstream pattern is height rises to the South, and possibly by then we have the Strat becoming more unfavourable - potentially a very mild mid to late December such as 1988.

Well today's pizza slice is bringing temps of 4C and a strong ESE to the corner of the S.E at the time of day of the max temp !

What I'm seeing is more than the usual uncertainty and no obvious long wave pattern for either mild or cold.

The height rises to the south on recent runs have been a function of the behaviour of the deep low pressure taking a southerly track and then losing its way, driving WAA ahead of it and pulling surface high pressure with it.

Agreed. Despite assertions, given the uncertainty, it is far too early to have any confidence re. December's weather at this stage.

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There does not look like much in the way of any notable cold conditions but day 7-8 are cold for Scotland and N England.

Changeable with both some dry and fine weather, and some wet rainy windy or breezy but showery conditions.

The SSW is not able to get rid of the UK side of the Polar Vortex. We are more directly influenced by winds from the SW.

I am fine with this setup.

Quite a lot of Amplification of the Jetstream, and NE Europe is looking wet and windy but in 7-9 days time it could be cold and wintry sometimes for NE Europe.

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10C down here in the south and nothing lower then 7C in past 24 hours... very much average kind of late November gloom.

Yeah, it is this situation that will by Tomorrow bring about milder - a few degrees above normal temperatures- mild sectors with SW winds, the high pressure ridging, but some days we will get wet and windy weather followed by another day of wet and windy.

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4.3 degrees C in Wanstead Park

Dewpoint 2.3 degrees C.

Wind 1.1 mph from the West.

Pressure 1010.2 hPa

Dewpoint 2.3 degrees C.

It is 2 degrees colder that forecasted yesterday evening. Cold air won today.