The postage stamp ECM ensembles only go out to 168, nothing much of interest on them for the time being:

https://charts.ecmwf.int/products/enplot?base_time=202312070000&valid_time=202312140000 

As ever, it's going to be a slog to get through to more interesting charts.

 

I've got ECM ENS mslp stamps out to t+364. Open in a new tab and then zoom for the best view.




 

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I've got ECM ENS mslp stamps out to t+364. Open in a new tab and then zoom for the best view.




 

Not exactly stellar, but not without interest.

Top row, right hand side would do for me, and there's a few perts that have a similar set-up.

Greenland high ridging south into the mid-Atlantic, low to the N/NE, combining to create a cold flow from the Arctic and a likely unstable NW'ly. I know wouldn't raise much of an eye in the SE, but for the bulk of the UK, that's always a promising type of chart.

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Great start on the 00z gfs run....looking good for Xmas snow for many down the east....going to change but keep the trend.....

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0z again isn’t without interest. It’s going to be fun the next few days watching how the MLB moves around. 

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Yep remarkable consistency from the GFS Op for HLB to return to Greenland about 22nd ish . These things rarely if ever countdown to the zero hour smoothly.  But atm best chance for a proper white Christmas in a very long time.🥶🥶🥶🤞🤞🤞

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A decent cold cluster showing up now about 22nd. Long way to go though.

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WX temp summaries show little change from yesterday; for two weeks they show freezing weather more or less static east of Poland (and including Scandinavia) and N of the Black Sea. W Europe mild and above norm in week 1, cooler and close to norm week 2. Of note, however, is that ultra-cold weather over Russia declines to norm for that area. Pptn also similar; for Atlantic coastal countries and down through France to the Alps, all clearing away in favour of a large dry area (new; Spain, France, Britain, even Denmark) in week 2 but today dry area also including much of C Europe. Rain on S coasts of Mediterranean.

GFS Op - deep LP currently S of Greenland (945mb) projecting a trough across Britain, to 985mb Hebrides tomorrow, the whole system filling and moving E-wards to 1000mb S Scotland Tue 12th (and link to 1005mb Baltic). The section over Scotland moves off to S Europe, pressure rises and by by Fri 15th HP 1040mb is centred over Cornwall. This pressure is maintained somewhere over Britain until Wed 20th when it first retrogresses and then moves N to Greenland 1045mb Sun 24th, at which time Britain is under N-lies controlled by LP 1000mb S Baltic.

ECM - similar to GFS but HP slower to move in, 1040mb not attained until Mon 18th, and then situated further S with SW-lies for Scotland.

GEM - somewhere between GFS and ECM

GEFS - mild (in S) or near norm (in N) to Wed 13th with pulses of rain, cooler around Fri 15th, good ens agreement to this point, then with increasing uncertainty milder again near Mon 18th (many ens members very mild) and a distinct cooling to below norm approaching Christmas Eve. Mainly dry after Wed 13th. 

 

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GEFS stamps are worth a look.


https://www.theweatheroutlook.com/twodata/gefs.aspx?run=na&charthour=384&chartname=ps_500hpa&chartregion=na-region&p=1&charttag=PS%20500hPa%20(GPDM) 


https://www.theweatheroutlook.com/twodata/gefs.aspx?run=na&charthour=384&chartname=ps_850temp&chartregion=na-region&p=1&charttag=PS%20850hPa%20temp 

I'll post the ECM ones later if I get chance.

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Both GEM and ECM ensembles have the same cold cluster starting about the 22nd. That's fairly unusual for something so far out.
 

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Both GEM and ECM ensembles have the same cold cluster starting about the 22nd. That's fairly unusual for something so far out.
 

They do and given previous experience it's just half an eye slightly open on this one at this stage.
The EC clusters do leave the door open for decent retrogression from the 20th but as always if the atmosphere can find a way of preventing a deep arctic push coming our way it will.
The first step will be to get pressure building close to or over the UK and that is well-modeled now. Then we wait to see if the signal (a weak one just now) for MLB to HLB via retrogression via a NW route, or better still for the Holy Grail via a NE route, is still there or strengthens.

As others have said, the pieces of the jigsaw are certainly there this year. We just need to avoid losing the crucial ones under the sofa.

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They do and given previous experience it's just half an eye slightly open on this one at this stage.
The EC clusters do leave the door open for decent retrogression from the 20th but as always if the atmosphere can find a way of preventing a deep arctic push coming our way it will.
The first step will be to get pressure building close to or over the UK and that is well-modeled now. Then we wait to see if the signal (a weak one just now) for MLB to HLB via retrogression via a NW route, or better still for the Holy Grail via a NE route, is still there or strengthens.

As others have said, the pieces of the jigsaw are certainly there this year. We just need to avoid losing the crucial ones under the sofa.

Channel 5 is showing "White Christmas of 1981" on Saturday evening.  At least we cannot rule it out at this stage, normally its a done deal by now for a green xmas

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Out to Day 11-12 and the jet stream pattern looks very similar to a few runs ago, with a strong jet streak heading SE from southern Greenland straight down over the country, whilst the southern arm of the jet is gaining strength over central and southern US.

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Gosh the 06z continues the theme. It really is thing of beauty.

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Some nice FI consistency here for Xmas
 

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Some nice FI consistency here for Xmas
 

Two different routes to get there, but the end result is the same - a chunk of the PV stuck over Scandinavia and us on the cold side of it.

I remember decades ago reading on usw that getting a winter high over the UK, something like 1040hPa or more, is often the precursor to a cold spell. While doubtless some would go on about wave-breaking and other overly technical stuff, it's more like a rock in a stream: it messes up the flow. We're seeing that with the GFS 0z and 6z runs, whether or not the ECM and GEM runs would get there if they went out far enough remains to be seen...

 

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Interesting if not very interesting - even for the populous SE quadrant of the UK -  as we approach the first day of winter on 21 December. Probably the best run-in we have had to the festive period for a while.

More runs needed, as the old cliche has it. 

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Decent op run just goes wrong for cold for Xmas. Keeps the interest up though

Decent op run just goes wrong for cold for Xmas. Keeps the interest up though

Yes, as soon as the HP doesn’t retrogress, and the jet stream coming across the US tilts towards the NE, the doors are opened again to a more westerly flow.

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Yes, as soon as the HP doesn’t retrogress, and the jet stream coming across the US tilts towards the NE, the doors are opened again to a more westerly flow.

slider for Xmas?

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slider for Xmas?

The control has a slider, running down to the west of Ireland.  Several of the perturbations deliver a cold northerly flow.

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