GFS agrees with FAX but the N-lies on Mon 24thare weaker and by Wed 26th W-lies are present all across Britain. As the week goes on, the controlling LP originally near Iceland moves S-wards and covers Britain 985mb Mon 1st. Later that week it's back to W-lies again, LP near Iceland, NW-lies at first, SW-lies by Sat 6th

ECM  takes the LP Mon 1st down to Spain instead, and then features HP1040mb Sweden, extnding towards Britain, and bringing up S-lies by Thu 3rd

GEFS mean temp slower to recover than shown yesterday, staying on the cool side esp in the SE to Wed 26th, then (with the usual caveat about spread of ens members) mostly above norm into December. Rain most likely around 23rd and 29th, not quite dry at other times

AIFS London maxima rising irregularly to ca 12C by Fri 28th before dropping off a bit, rain quite frequent but not heavy from Sun 23rd onwards; Edinburgh similar to London but rain more persistent

That’s a bold prediction…. 😉

🤔😂

I will say I rate the MJO phase far more than stratospheric warming signals. But in any case the phase 7 MJO looks to be due right at the end of this month or start of next one, so plenty of time for models to show more interest. 

That doesn't really tell the full story.

There's been a consistency to models showing that on the opposite side of the Arctic Circle to ours (far North Pacific), high pressure has been pretty resolute. Even when it's been driven back southwards, it's generally rebuilt. 

This is only really apparent when you look at the 'top down' northern hemisphere view. Our problem here in the UK is that there continues to be rampant cyclogenesis in that Baffin Bay / Labrador Sea area covering western Canada and Eastern Greenland. It's creating some monster lows. IT looks to be caused by significantly high SST anomalies in the area .

The recent HLB (which for a time was proper cross-Arctic blocking) helped keep it penned, and actually diverted one or two onto a more southern jet trajectory. But the HLB is now declining and the flood gates (could be literally!) are opening.

For a while, the models do show what looks to be the PV assembling for winter. But pressure on the opposite side of the Arctic Circle soon muscles its way back. This is showing on each of GFS , ECM  and AIFS 

It doesn't immediately improve our weather - because high pressure to our east adds to that in the north and south to 'kettle' the troughing over western Europe.

But by the end of each of those runs, there's a lot of promise (I know, I know!) because there's high pressure over the Pole that's starting to inch our way and, on GFS and AIFS, the door is open to our east, with energy sliding eastwards.

For me, AIFS is the pick, in terms of promise:

https://expert-images.weatheronline.co.uk/daten/proficharts/web/en/ec_aifs/2025/11/20/basis06/nhem/pslv/25120506_2006.gif 

I personally don't really seek cold from the east - certainly not at this time of year, where (unless it's a long-fetch from the Lapsley & Kara Seas) there isn't the depth of cold to deliver anything superb to us. No, the best source of cold in the first half of winter is from the north, delivered by northern blocking. My preference is the blocking to be to our NW, but that's by the by. Every notably cold & snowy December I can remember in my lifetime (78/81/09/10) have been founded on blocking centred to our north (more or less Greenland Highs), even if the synoptics evolved as the cold/snowy spell progressed.

The difference between now and 120hours from now is that yes it has got a bit stronger but in both cases it sits over Siberia, not canada. Even if the pattern becomes briefly zonal it will not be a stable zonal flow as it would be if the polar vortex was situated over Canada. I'm quietly confident that any mild, unsettled weather will be brief and the next 30 days will be mostly cold and dry.

Yes, that is why they are called background signals. It’s a complicated business this weather forecasting stuff and all signals, background, foreground, not even in the ground and a few chaotic unpredictable ones all add up to making the complicated picture. 

There are factors that have been nicely discussed earlier in the thread that should, based on scientific evidence and precedent, be considered when looking ahead. However there is also the NWP output, which by and large is a bit discouraging currently if people are looking for clear signs of wintry weather. That could of course change, and being autumn still I’m not overly bothered.

Thanks for the observations and well

written overview. You’re quite right to point out the NH overview. I had a look at lunch, and you can definitely see some puzzle pieces coming togeather. 

As ever, the taste of the last few days has me craving for more. Patience grasshopper for me comes to mind. 

Also, I’ve noted in the immediate term, that next week looks quite cold again looking at the latest ensembles

I do. Cold from the east (with high centered over southern Scandinavia/western Russia) is higher quality. The type of deep, dry cold that you can still wear a teeshirt out in because it feels good. Plus, you have a higher quality of sky. Deeper blues and sparkling purple nights. 

Miss the industrial haze from The Ruhr and the Soviet Block.....

Also looking at temperatures in the stratosphere - well isn't this interesting? again it is only one model and one run but we are seeing temperatures increase at 10hpa and 30hpa over the Arctic regions and look at this chart at +384z - it is showing that the warming is intensifying over Siberia - Usually this is a precursor of an upcoming SSW!? So one to watch! Keep in mind the temp at 10hap over Pole should be rapidly decreasing NOT rising and the PV should be strengthening along with zonal winds NOT weakening. - One to keep an eye on surely. Given we have a La Nina in combination with an easterly QBO and a wetter than average autumn compared to recent years gives us hope ...

Just look how the temperature rises towards the end of the run esp over Russia/Siberia. and the displacement of the PV is evident already so early on:

https://www.theweatheroutlook.com/charts/gfs/18_384_arctic10.png 

"Its the hope that kills you" my friend.  We go through the same shenanigans each year.  Selective background signals giving hope but it always fails.  

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202511200000&projection=opencharts_europe&valid_time=202601050000 

It really is like a light switch at the moment. ECM shows no SSW = pinks, ECM shows an SWW = white. 

EDIT: And the pressure anomalies show slightly higher pressure to the NE, lower to the south and west. That'd imply lows tracking further south than usual, and tallies with the MetO's 15-30 day outlook, which is pasted below:

https://charts.ecmwf.int/products/extended-anomaly-mslp?base_time=202511200000&projection=opencharts_europe&valid_time=202512290000 

There is an increased chance of settled spells at first, bringing more in the way of dry weather, light winds, and increased risk of overnight fog and frosts. This is associated with more frequent high pressure which will probably never be too far away to the north or east. Whilst spells of wind/rain still remain possible they may be less frequent than usual at first, but a steady increase in periods of unsettled weather across southern and/or western areas in particular seems likely as the period progresses. Above average temperatures are slightly more likely overall, but colder spells, especially at first and in the north, could still occur. One or more spells of snow cannot be ruled out, should weather systems arriving from the south, push north into colder air.

https://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=10&forecast=f192&lng=eng&hem=nh 

There seems to my eye to be a lot of application of the jet upstream of us, with organised PV jet only over the two oceans. predicting the fire-hose jet thrashings - as the anomalies of SSTs and aforementioned influences (QBO, MJO, ENSO Etc) that might cause the fireman to drop the hose, is a complex area - as Doc States, but that amplification upwind often ripples along downwind (so to speak) and these background factors might then favour periodic blocking. Over in the east - interludes of wetness are still welcome, to fill ever greater depletion’s in the aquifers. I do hope the blocks repeat, as IMBY - I didn’t see a flake: (although it was all about in places east and west)!

GFS - builds on the HP suggested by Fax and, with a brief interruption as LP slides past Scotland Mon 1st, produces HP often 1035+mb centred over Britain through to Sun 7th (but source of air was originally from SW so I suspect fog rather than frost)

ECM - disagrees with GFS with a regular passage of LPs passing N of Scotland through the Faeroes, driving W-lies for Britain and little effect of HP away from the S Coast; only on Sat 6th does a broader ridge of HP affect Britain

AIFS - no clear pattern, London maxima in the 8-10C range with occasional rain until Thu 4th when heavier; Edinburgh maxima nearer 6C with more persistent rain; both stations have a markedly milder day Thu 27th

GEFS - in the S cool to Thu 27th with rain on 23rd, very mild in most ens members Fri 28th and 5th (Op 10C above norm on that date!) and generally on the dry side. In the N, similar but not quite a mild, and rain at intervals, often heavy in the west

I totally agree but I was just making a point that we have not seen a warming of a stratosphere at 10 and 30hpa this time of year and a weaker PV that's all I was saying. But we can only hope.

https://www.theweatheroutlook.com/twodata/ecmhr.aspx 

The parameter is provided in metres of water equivalent. For the conversion I've assumed a density of 0.15 g/cm³.