https://charts.ecmwf.int/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202511280000 

The 45-day ECM weekly charts show a gradual cooling trend through December, with Christmas week being average (ref 91-20 means) over most of the UK, so worth keeping an eye on.

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202511280000&projection=opencharts_europe&valid_time=202512290000 

EDIT: Looks like it was a really brief SSW. By noon yesterday it'd recovered to +0.4.

https://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=10&forecast=a12&lng=eng&hem=nh 

(Sorry for lack of detail) 😉

FAX: trough and fronts today mainly for England resolving into LP 991mb moving off across the N Sea but after a day's respite, fronts being pushed across the country through to  Wed 3rd by a mid-Atlantic LP ca 970mb (MetO rain warning for the S Coast Mon-Tue). That LP eventually reaches Britain as a decaying trough but a new LP is being lined up to take its place.

GFS Op: as above and then series of depressions arising on the Atlantic and affecting the British Isles before filling and making way for the next one. The closest approach of the deepest LPs is shown as 980mb Ireland Sat 6th, 975mb N Scotland Wed 10th, 985mb Rockall Mon 15th, but no doubt with such a mobile situation the timing and placement will vary.

ECM: similar (and slightly confused) mobile situation but with a tendency to push troughs ahead towards S England  (995mb Sun 7th Calais, 970mb Sat 13th Cornwall)

AIFS: London maxima mostly 10C (cooler tomorrow, milder Tue 9th), some rain on most days. Edinburgh, similar, but maxima a couple of degrees lower.

GEFS: cool and (for one day only) dry tomorrow, otherwise mean temp near norm and rain in most runs on most days, mostly light in the east but heavy in the west 

Another boring mild green Christmas in prospect.  If we cant have cold then I'd rather it go the opposite way like 2015 on steroids.  

This is my location but other areas are very similar:

GEFS 00z ensemble data  (other models show a very similar picture)

It looks quite unsettled throughout the next couple of weeks with potentially a lot of wet and windy weather around but nothing too notable in terms of mild or cold conditions for the duration. The usual caveats apply of course and things will no doubt change, especially in terms of specifics as time goes by, as is always the case.

ECM 10 day mean would suggest more average temps broadly speaking. Mild if you are more favoured toward cold, but will still feel cold due that near constant stiff mP flow. 

Back on topic. I looked at the 18z gfs. What a dire set of runs. I mean seriously boring days maxes of 10 or 11c and nighttime lows of 8 or 9c with rain and mucky murky drizzle and light rain. I looked at the low pressure systems and it appears as if they are all coming from the SW and when they pull away they pull away to the NE allowed another low to form, instead of the low going eastwards pulling down a temporary NW airmass. ECM offers no hope either for coldies.

Meanwhile the cold in eastern Europe continues and N America are getting a taste of winter and it isn’t even winter yet. Why can't the UK get anything wintry? Where is the winter 25/26 moaning thread?

FAX: As one LP moves away, so another develops on the Atlantic and moves towards Britain, arriving 985mb Cape Wrath Tue 2nd and again 983 mb Ireland Thu 4th, with another waiting in the wings 969mb, all the time pushing fronts across. Any HP somewhere north of the Caspian.

GFS Op: LPs as above (that on Thu 4th looking stormy) continuing to run from Atlantic to NW Scotland but with a break in the pattern Thu 11th when LP 975mb develops in situ in the N Sea with E/NE-lies for a while as a ridge of HP spreads from the north, 1030mb Scotland Sat 13th but all of Britain by Tue 16th

ECM: like GFS at first (Thu 4th less stormy) but Wed 10th a cold LP comes in from the NW 960mb N Ireland and no indication as far as this model goes that there will be NE-lies.

AIFS: London, maxima mostly around 10C for a week , then milder before cooling again, rain on most days. Edinburgh similar but a couple of degrees cooler

GEFS: mean temps near norm to Tue 16th but as Ballamar above notes, the Op does its own thing after the 11th and around Sun 14th is 10C below norm in the S, out on its own (still noticeable but less extreme in the N), Rain on most days, perhaps drying up towards the end of the period and never very heavy down the E Coast

It'll arrive when Autumn finishes and Winter starts???!🤣

The GFS is on to something - perhaps Retron’s SSW reversal, which might have been in just the right spot to inflate a HP over Scandi- and deliver an old fashioned easterly, albeit less cold than the days of old - 60s to 80s, but snow shown nevertheless, just not settling on lower ground. All in FI - but the GFS does have a trend picking lead on the other models IMO. However, verification now needed, or this straw will be clutched to crumble like the Many dreams of a white Christmas, or a white anytime. Keeps the interest alive!! 

I noticed that too. The GEFS London 00z op has gone off on one in a big way at a bit more than 10degC below the mean, as mentioned in DEW's analysis. But it's FI at 11 days away so I don't expect anything like it on the next run. 

Over just the last few runs, we could be looking at a +9 or a +2 December CET.

The models seem to show background 'trends' after the 240hr frame. This morning's GFS goes for a dive - after 240hr. This is where FI starts at the moment. Sometimes, FI can start at 72hr, so we should be (kind of) grateful that the models have useful predicting, even if the weather is not that useful. A few days of staying in and watching the rain!!

Cheers all, take care.... DB68 

Just looked at the latest GFS update (06z op) with that above date to mind. BANK! I would absolutely take that. Mild, calm with mist. That would be perfect if that came off.

PS: The control and AI I'm less happy with and ECM can go straight into the bin.

A sudden swing in the output is on the way IMO.

Perhaps, the models have been playing around with high pressure to the N/NE on and off for a few days now but it’s never been a consistent signal and interspersed with persistent westerly weather. Things could change and the hints are worth keeping an eye on.

I'm given to understand from another thread that a SSW did occur on Friday just past. FWIW, I am not suggesting that will have any kind of positive impact on our weather from the point of view of cold seekers. However, I do know from when SSWs have happened in the past that they cause no end of problems for the models when it comes to working out how the effects of them play out.

Hi David,  yes, there was a brief, slight wind reversal 2-3 days ago. Last week’s Met Office Deep Dive covered it and it was noted that SSWs are extremely rare this early in the season and that the models might have some issues interpreting the signals.  However it was also stressed that SSWs don’t always propagate down into the troposphere and even when they do there’s no certainly that a block will establish in the right place to advect cold weather our way.