Mr Fergusson has already clarified that the signal is from GloSea5 for a warming in the stratosphere - not from MOGREPS or ECM. Given that Adam Scaife said in a Met office presentation, the model lead time for SSW is about 3 weeks, it will be heavily caveated and perhaps not even relevant. Remember last January and the change in the wording of the 30 dayer - that was also predicated on a GloSea5 strat warming. Model was right about the warming but no change in pattern due to extreme vortex strength.

                                            ............................

Current indications suggest the unsettled start to January is more likely than not to persist through the middle to latter part of the month. This would mean spells of dull, wet and windy weather alternating with brighter but colder and showery periods, including some wintry showers. Some signs are also emerging suggesting temperatures being less mild in general terms than the last couple of weeks, and perhaps even significantly colder late in the month.

Updated: 1139 on Sat 28 Dec 2013

http://www.metoffice...st_weather.html

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The warming has first to materialise, then see how/if the pieces fall, before anyone can begin to have a stab where blocking might be.

Please explain your reasons behind that comment

Yes far from Blocking! Looks like there is what 3,000 miles of nothing (high pressure!). - At least it will be dry - But not looking good for the Alps. Poor start to the ski season.

I think I understand your principle, but what do you define as the timeframe when signals become more founded and solid? The MetO are indicating patterns that may develop in over a month's time - not what we see on any model output available to us (except CFS, and the verification at +600 is, were it to be published, likely to be next to zero).

I've been around this business for the best part of 45 years and believe me, if the MetO extended outlook - that bastion of reason and conservative thought - even hints at a significant pattern change, then I'd take more notice of it that many an LRF, the majority of which are pure guesswork.

And as for the ridiculous criticism of Ian F (not you by the way), at some point it will have to be severely sanctioned by the excellent moderation team here or else we'll lose the patronage of a pretty decent professional IMO. Trust me, the minority that nit and pick his tweets will be crying out for his inside info if and when the snow starts to fall.

I feel like a surfer waiting on the beach looking way out to sea to catch a wave to roll in on.

Nothing showing yet.

thanks I see that now on this computer but at work there was a different number of numbers per row and I was sometimes having to jump to the middle of a row. I will try to take a screenshot if I see it again.

Cheers.

This was the same picture we were seeing 1- 2 weeks ago, and i suspect - looking ahead - will be the same pattern we see going into the 2nd half of dec and over the xmas period.

ie, temporary (but not very potent) plunges of colder air - replaced by HP from the west and milder uppers.  With any colder weather for southern parts delivered when HP is back in command and we get clear skies.  Snow for the mountains, raw wind.  Sunny days.

Being serious now, I did enjoy the looks of the low res-end of the 6z GFS run by seemingly "trending" with the idea of high pressure properly taking a hold over the UK in the run up to Christmas.

But it is a long way off in forecasting terms and I'm sure it'll all be snatched away in the 12z run as I tend to think of the models often waking up in a bad mood in the morning and having it out on us by showing less desirable looking runs.

Next week's pattern just keeps on looking flatter.

The  main culprit is a very strong jet stream that keeps being upgraded in intensity, now looking to be over 220 mph which is right toward the top end of the range.

As the subtropical jet (or southern arm) fires NE for a couple of days, warm air from the subtropics is thrown perhaps as far north as Southern England, while at the same time very cold Arctic air plunges south through Greenland. This creates a huge contrast in air masses that looks to be present over the middle of the North Atlantic Tuesday-Wednesday.

Originally, a low tracking from SW Greenland to the UK looked to move along quickly enough to dive SE ahead of the influence from the subtropical jet, but it has since been adjusted to a slower feature, which is unable to dive SE and also increases the extremity of the clash of air masses and hence the strength of the jet stream.

While that seems like yet more bad luck in a season so far riddled with it, we should perhaps count ourselves lucky that there doesn't look to be a major storm system situated in the right place to make the most of this, though given that it's still 6 days out, a rapid shortwave development can't be ruled out.

So, this period of raging jet looks to leave the atmosphere with a lot of work to do before colder conditions are able to return to the UK, as the Azores High is able to extend well east into Europe with flat westerlies and an abundance of mild conditions across England and Wales in particular. In fact, the middle part of next week could be about as mild as it gets at this time of year.

Beyond that, I still see the behaviour of the subtropical jet as a critical component in developments.

What we need is a nice cut-off low to form which can then sustain a strong East U.S./Canadian Ridge, cutting off the fuel supply to the Atlantic storm train and encouraging the Atlantic jet to track further south:

...as opposed to a low which is still tied to the main Atlantic jet and progresses NE, causing the East U.S./Canadian ridge to start collapsing:

Funnily enough this GFSP 00z run does then manage to about-face, as a cut-off low forms on the right-hand chart above and just happens to combine with sudden height rises in the Arctic to drive the ridge in the western North Atlantic right up through Greenland, giving a decent 24th-25th December:

This does represent the sort of thing that could easily manifest as a result of the polar vortex displaced increasingly far from the Greenland/Canada regions, but I reckon the stronger high on the ECM run would provide a more stable result than the above, which collapses after a two day wonder.

That ECM run seems to be the most favourable on offer this morning, with GEM close but not quite cutting the mustard.

The fact that GFSP still produces something does at least reflect a weakening of the Pacific Jet (actually very marked on that run) which reduces the ability of disturbances to push through the U.S. and on into the Atlantic without being held up by ridges of high pressure. That represents the removal of what has been a major spanner in the works of late.

I think that's the most depressing & hope-devoid post I've seen from you in recent times, Stormchaser.

I'd been quietly confident of a bit of a pattern-change to northern blocking as Xmas/NY approached, but I now think this won't happen. Very sad - I love the chaos a cold & snowy spell brings just before Xmas.

So do you not agree with this??

Outlook for the UK over the next 6-30 days

UK Outlook for Monday 15 Dec 2014 to Wednesday 24 Dec 2014:

Cold and clear with dry and sunny conditions expected for many parts on Monday. However, there will be showery conditions following onto exposed northwestern coasts. Cloud and winds will then increase from the west with rain, and hill snow running along the leading edge, spreading into the far west later in the day. Through the rest of the week and in the run up to Christmas, conditions should remain unsettled with periods of rain and strong winds, interspersed with clearer, colder conditions with showers, these wintry at times, perhaps even to low levels in the north. There will be large differences in day to day temperatures dependant on each days weather, but perhaps averaging out slightly below normal.

UK Outlook for Thursday 25 Dec 2014 to Thursday 8 Jan 2015:

The last week of December will most likely stay unsettled and often windy with weather systems arriving from the west or northwest. It is likely that the UK will see cloudy periods with spells of rain, but that these will probably be interspersed by clearer and colder conditions with showers, which could turn wintry at times, mainly in the north. The most unsettled conditions are likely to be in the north and west. However, there is a signal that conditions may become colder particularly into the New Year, although there is a large amount of uncertainty surrounding this. Temperatures are expected be around average for the time of year, then may turn colder than normal in the New Year.

Updated at: 0227 on Thu 11 Dec 2014

A word on the ensembles - the majority of the GEFS don't have the cut-off low which means the pattern remains rather flat in the Atlantic sector. 

There is some serious amplification to the U.S. pattern though, with a marked ridge over the western half and trough over the eastern half, which I suppose reflects the weaker Pacific Jet. If anything this makes the behaviour of the subtropical jet even more important, as you could get a serious mid-Atlantic ridge out of that but only via the cut-off low scenario that I discussed in my previous post.

The ECM ensembles appear more evenly spread with regards to the cut-off low. The mean across the Canadian sector suggests that the operational run was at the extreme upper end with that Canadian ridge, but doesn't support low heights there either, so it looks finely balanced.

Overall, the only signal that is really consistent across the output is for a gradual reduction in the strength of the zonal progression, which should reduce the rate at which conditions fluctuate and allow ridges of high pressure to have a bit more control over our weather.

The potential results tend to be very widely spread when such trends are present so the ensembles may start to wander around all over the place.

...and after all that I've just written, the GFSP 06z calls into question the behaviour of the subtropical jet days 6-7, a few days earlier than I was focusing on:

See how that low in the western North Atlantic is separate from the one just south of Greenland? Those two features phased on all of the 00z model output.

The consequence for day 9 is this:

That shows just how important the subtropical jet behaviour is going to be!

It's a variation on the kind of adjustment that took place with respect to the trough behaviour tomorrow.

It seems we should place little faith in any particular model run at the moment.

Not when I will be traveling you don't!

We have January and February and even March to come yet.

Thanks for unravelling the mysterious comment - that the clarification is indeed helpful 

You could well be right it's 50/50 I would say. The very latest Strat talk seems to be a bit disappointing. We will need a lot of luck. It's our only straw at the moment though as the output is very average at best.

 So as some of knew, there was no hidden agenda or withholding of information. Thanks for confirming. 

Milder next week , then cooling off again. Too far out to see any effect from the STRATOSPHERIC WARMING