There’s always a party pooper (in the guise of a sensible level-headed approach of course).

At this stage it’s not about what is actually showing but the potential it might lead to so please allow the glass half full contingent (of which I am one) a little slack 😉

TBF the outlook is actually a rather cold one for us in the south, going by the ECM-46 anyway. It's been pretty solid on this for a few days now and I suspect it'll verify. The main question is how much influence the high will have and where it will end up. It doesn't take long this time of year to build an inversion under light winds.

The 12z GFS is a thing of wonder in terms of synoptics down here, a midwinter easterly complete with upper cold pool moving westwards just to the south. It's been a long, long time since we saw those sort of charts at this time of year. 

It's still such a long way off though that even if it did verify the 850s would doubtless be quite different from those shown. Those upper cold pools, incidentally, are excellent news if it's snow you're after from an easterly - lower heights mean instability and a trough or two in the flow.

Under any clear skies, it can still get very cold under warm 850s from Europe, especially if winds remain near calm. 

Don't bother, Neil. He's just a troll.

Yep, until there's a bit more agreement on that LPs behaviour, seems a bit pointless getting too invested in the longer term. That said when I had a quick look earlier at the GFS 6z ens the nice thing was that HP became dominant whether the LP heads south or north east. On balance I think there were less 'nice' solutions when it did so probably because the start position was for HP further south as no HP over Scandi helping to suck it north/deflect the jet/insert more technical explanation but the set ups were still generally chilly.  

At least the setup has something to talk about beyond, low pressure for the whole run, which makes a pleasant change!

To be fair most easterlies are a waste of an easterly. 😉

I’ve missed the prospect of cool drizzly anticyclonic gloom (although to be fair it is marginally better than mild, wet and windy conditions).

The Christmas period continues to look a bit on the cooler side of average but nothing overly exciting currently.

😄

You sound like a slightly less depressed version of Richard…. 🤔😉

The far reaches of the ECM output once again tease with the possibility of, eventually, some sort of retrogression of the block and a bitter Arctic northerly. 🙂

Yes! - Both control and Operational 18z plunge us into the freezer at the end of the run - again early stages but signals are growing for a cold and wintry spell after a period of dry and frosty weather over Xmas. Hopefully this trend to cold continues...

I think the model is picking up on the weak PV/zonal winds we currently have at 10hpa after the warming and displaced PV we had 1-2 weeks ago!? 

Yes that’s the weird factor for me, just how such an organised and raging zonal jet appears to be forecast to collapse to something very weak And extraordinarily amplified indeed in such a short time frame, especially for the time of year, when historically it would be strongest. Not that I am complaining, but a jet anomaly chart would surely show this as extreme. I suppose this weak jet is reflective of the background signals and predictions, associated with easterly QBO, La Niña, Phase 7,8 or 1 of MJO and negative NAO/ AO  emerging, but it always seems a surprise when a blocking winter pattern emerges these days, especially at Christmas. I did read somewhere that the little ice age was in fact a warm period globally, and that favoured a weakened jet. This would then favour a negative NAO and colder winters in NW Europe, but since the affects of GW are 3 x that of the warming during the ‘Little Ice Age‘ I am not convinced by that theory, at least to date!!

Yes, but considering how hideously mild its been for many Christmases, anything less than10 would be considered cold!

The chances of snow are very slim, next to nothing but at least hopefully it will feel like Christmas should be. Or at least the myth were are brainwashed with by Bing Crosby

Yes and if this verifies we could see the coldest Xmas day for many years!?

At the moment I just want dry weather if we can't get snow - anything to get us out of days of wind and rain time and time again!

Yes you're right both AO and NAO are forecast to go negative and although we didn't see a major SSW we did see a SW and a split PV and because as you said zonal winds are weaker than average in combination with easterly QBO we are more likely to see HLB. My knowledge of the MJO isn't that great though. But the switch is quite sudden and extreme. That being said La Nina winters are usually front loaded winters such as the winter of 2022/2023 when we last had a La Nina winter cold first 2-3 weeks of winter and 2nd week of January 2023. Also the NE states/Canada will be warming up by Xmas which is good news for us as we (UK/NW Europe) won't see so much cyclogenisis/low pressure systems developing off eastern seaboard of USA/Canada racing across the Atlantic and there will soon be more of a chance for blocking ridge to build and strengthen.

Hopefully the stratospheric warming we had a week or so back (very early in the season) is a precursor to a major SSW later? The chances of an SSW in an easterly QBO winter is around 70-75% I heard. That being said not all SSW's denote colder weather for UK. The weaker PV clearly delivered a very early cold and snowy spell to the USA/Canada recently which was unhelpful for us here!

BUT soon the pattern is changing there and I think we could see a very wintry end to the month and into the New Year. But it will all depend on where this ridge of HP goes after Christmas. Anything BUT relentless wind and rain for me - I miss my walks as well. I still think this could end up a much milder than average December because even an easterly wind won't give us much bitterly cold weather with snow simply because the airmasses in Europe has been usually mild/warm for the time of year and the weather in Europe including Scandinavia, Baltic regions so far this December has been well above average and many Scandinavian cities are still seeing both daytime and night-time temperatures well above freezing, so Europe needs to cool down as a whole.

Sorry, I have gone off topic - So back to models, the 18z 850's ENS temps show quite a few colder runs now appearing in latter stages with some several going down to -10c and a few down to -12c @ 850hpa!

This morning's ECM-46 still shows the same, FWIW, blues over much of England and Wales for Christmas week, deeper blues the week after, then lighter blues again for the following week. Thereafter the anomaly becomes neutral.

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=1&run=0&time=240&lid=OP&h=0&mv=0&tr=3#mapref 

I want to try my new tyres on snow. You've made a old man very happy.... 😉 We live in hope.

https://charts.ecmwf.int/products/extended-anomaly-z500?base_time=202512150000&projection=opencharts_europe&valid_time=202512290000 

https://images.meteociel.fr/im/22/23563/ECM101_216jze2.GIF 

Care has to be taken with those anomaly charts, mind you, but the overall picture is most encouraging for cold fans down here. 

I’ve been watching with interest and will not be holding my breath. We all have been led down the garden path in the past ..sometimes as far as the actual garden gate only for the charts to collapse five days from verifying.

GFS Op 0z - As FAX to Fri 19th, then the LP NW of Scotland takes a change of direction (as shown yesterday), running SE-wards, 985mb Biscay Mon 22nd and then translating into a general area of LP over W Europe while pressure rises 1035mb Faeroes Wed 24th. This persists through the Christmas period with E-lies for England and calm weather for Scotland. By New Year the HP has regressed into the Atlantic and strong and quite cold N-lies are blowing down the E Coast. (At this point S Scandinavia is really cold  and LP centred there implies heavy snow fall).

ECM - A deeper LP and much more disturbed weather on Fri 19th before this  model joins GFS with LP dropping S-wards to the Continent. It does however place the developing HP over Norway for Christmas Day, with no more than a light E-ly drift for Britain. Then the N-lies set in earlier, though weak, on Sun 28th, and on New Year's Eve an arctic LP near Spitsbergen is temptingly poised to move S-wards as blocking stretches from Greenland to mid-Atlantic.

AIFS - London, maxima about 10C with a little rain until Mon 20th, then cold with overnight frost until Christmas, recovering to 5C and dry. Edinburgh, maxima about 8C with some rain to Mon 20th, then mostly dry with base maxima 5C interrupted by very mild peaks ca 12C Fri26th and Mon 29th.

GEFS - postage stamps for T+180 (Tue 23rd) LP  near Greenland, HP SE Europe, some showing te start of the journey of the S-ward tracking LP which thus (alas!) is not nailed on. Line graphs, mild now, soon dropping to norm until Christmas Day, then a lot of uncertainty in ens members; in the south they come together from Wed 29th and mostly agree on 2 or 3 C below norm, op and control several degrees colder but in the north uncertainty persists with mean near norm. Rain in pulses, Wed 17th, Fri 19th and Mon 21st (only the 19th in NE), then mostly dry. 

Snow row figures still mostly in single figures (/33) starting from Christmas Day, but a definite uptick for England to close to 10 for the New Year