Regarding AI vs real, they are starting to look more similar now. We ended up with a solution that looks about halfway between them which is interesting. In terms of what happens now, small upgrades or downgrades could obviously still make a big difference and further ups and downs are likely to come. No reason to be pessimistic as things stand though.

Remarkable GEFS mean T+384 chart. I cannot emphasize enough how rare it is to see easterlies at this range. It means the long term outlook for cold is as good as it can possibly be (although that still doesn't mean its likely given the baseline is very unlikely). 

That is impressive given the timescale.

Going to do a flip -flop on what I presumed earlier. After the 12Z  OPs it now looks like they are actually coming together a little for this time range. It is now what comes after "universally"

Other than that snapshot, the GEFS look decent with the scatter mostly in the cool to cold range and the majority of members colder than the op in the longer term. The MOGREPS set has for the first time got more than 1 rogue colder member down here (3 this time) and the ECM looks reasonable if not overly exciting deeper in FI. 

A classic spell is still unlikely but something chilly, maybe cold is looking like a decent bet as it stands. The transition from LP to the west/south west from now to D9 or so is a little 'fraught' as patterns go but at least the current consensus is for it to more than likely work out to some degree.  Hopefully the ECM ens continue the reasonable theme. 

(GEM if you're looking for an obvious fly is pretty boring up to D10, no idea what its ens look like). 

There was of course the first two weeks of February 2012:- 

U.s.weather 31,930 Messages

Subject

*European overview* 1st February 2012  Keith (Southend)G  02/02/2012, 18:49

Otter Valley, Devon - C-c-c-c-c-cold! 6 more weeks of winter Nick Gardner 02/02/2012, 21:23

met office still going for milder weather and near... .02/02/2012, 21:34

Deathly cold    Stan  Widespread frost on Wednesday night: Shap ....Joe Egginton < 03/02/2012, 00:26

Brussels sunny but bitterly cold    Colin Youngs      03/02/2012, 01:03

Today's model interpretation  Darren Prescott  03/02/2012, 05:01

[OBS] Tideswell, Derbyshire -    Norman        03/02/2012, 07:05 

I see you were still getting up early Darren!  I remember you were doing DEW's job on USW back  then. I would have loved to have seen your analysis that day. Sadly I only have the headers of the posts now not the content The next day we had heavy snow and those first two  weeks of Feb 2012 I ended up with about 20cm and 4 days of falling snow and 9 days of lying snow. 

Though one can no longer post to newsgroups usiong Google Groups, it's still possible to search their archive, and I eventually found Darren's post:

https://groups.google.com/g/uk.sci.weather/c/UWI-Rs1ZPt0/m/npx8-4QqHXcJ 

I'm surprised that I don't remember that cold spell at all, though admittedly my memory is pretty fallible these days. I suppose it may have been rather overshadowed by February 2009, 2009-10, December 2010 and the winter of 2013. That period was probably the most recent example of the tendency of cold winters to come in "clumps".

-5c to -11 uppers from T240 to T360, some snow showers IMBY briefly and a front moving west to east bringing a spell of snow for some. In true 80s style it fizzles before it gets to MBY. 

Midday temps on the London set are:-

25/01 -> 3c

26/01 -> 4c

27/01 -> 3c

28/01 -> 3c

29/01 -> 1c

30/01 -> 1c

31/01 -> 1c

01/02 -> 1c

Caveated by it's deep FI, one run etc. but 8 days of chilly to cold weather isn't a bad result. The ens are 'reasonable' although again more scatter above the LTA than GEFS set and the op is briefly one of the colder options. The majority of runs are below the average though by the end and there's some properly cold runs which is reasonably unusual for ECM. Looking at the precip spikes there's a a fairly noticeable signal for precip in FI (London) and not a strong snow signal so there's presumably quite a few that have LPs wandering through with chilly air (IMBY) but not cold enough for the most part for anything fun.

I'm fairly happy with things this evening looking from a coldie POV and with an optimistic hat on. Below average more likely than average or above average and a low chance of something cold. Could be better but it's usually far worse chart viewing and actual weather wise so it's all good. Avg temp wise I'm tracking at 3.1c for January - doesn't look like I'll beat last year's 3.3c unless we do get colder air a bit quicker but it will I imagine make it 3 cool/avg Januarys in a row unless we flip to milder and that'd be a thoroughly reasonable result. 

From deep LP, low heights to this in a couple of days:-

That T180 chart also shows Easterlies across the UK and colder uppers for NE quadrant and chilly air for some others.

Yes, I thought the ensembles have improved as the day has progressed.

Indeed, it seems Darren missed it in his forecast. I believe it was unexpected and heaviest in Essex and Kent although quite widespread as Portsmouth and of course Dartmoor get mentions. That night we went to a 60th birthday party and were shocked by the road conditions when we came out to frozen roads and heavy snow over 10cm deep. As I said it lasted for 9 days and there was a low max of 0.4C during the period. By Feb 23 rd temp was up to 18.3C!

Well the 18z doesn't seem terrible so far 😜 My guessing how runs are going to go has been 'spotty' but I'm confident things would at least stay on the colder side of normal from there.  If we all face east and inhale deeply, maybe things would get even more interesting!

Edit: Hah! Guessed right for a change (okay, I picked a fairly certain bet):-

Ok, no more likely to come off than this mornings milder and more traditionally unsettled 6z GFS op but the pixels looks nice and I've had some unexpectedly strong homebrew cider so I'm feeling very mellow😶

6 days is a long time in UK weather forecasting, but if you're looking for cold, wintry weather, it's looking increasingly likely to happen from next weekend. 

The detail has yet to be decided. Could be nothing exceptional and short lived, or it could be something notable. 

Hats off to the AI models if this happens. 

- We will probably see a cold spell of some sort

- There is a chance (probably closeish to but less than 50%) we could get a direct hit from an impressively cold airmass (1 in 5+ year style event)

- If it happens it will probably not be before Next Saturday

- Expect a couple of days to be lost as we get closer. Saturday is a best case scenario, but a mid case scenario is probably more like Monday

- There is still a reasonable chance the cold spell could be a fairly run of the mill cold snap with a few days of marginal easterlies followed by anticyclonic conditions and then a rainy/snowy breakdown. I think no cold snap at all is becoming unlikely though.

More on this event over on the Cold Februaries thread.

By the time the cold air reaches the south, the block is weakening and most models show it being blasted away. So at best, a brief cold spell for southern areas.  Looks better for Scotland and northern england as you will tap into some proper cold uppers

It does feel rather like chasing a rainbow for us in the south - the deep cold, if shown, generally lurks beyond day 10. 

I'm not expecting much from this, TBH; the blocking to our NE looks likely to just cause a wet spell down here with temperatures eventually dropping a bit below normal by this time next week (so colder rain). There's a greater chance of colder conditions further north, but a classic Scandinavian High it's not. 

I've been keeping an eye on the GEFS, as that's the model I've looked at for longest over the years (as the ECM ensembles were largely inaccessible 15+ years ago). It's been hovering around the 30% mark for -10s for London, going as low as 15% over the last week and as high as 50% just a day or two ago - the 18z set last night was 33%. The general picture though is that although deep cold is possible, it's not likely. In previous decent cold spells that chance has generally crept up over time, usually by the 1 week out mark, and I'd be looking for a similar increase this time before I get too interested. 

Nonetheless, it remains a different period of model watching to the winter norm, it's a refreshing change!

I agree that the GFS 0z has been a bit of a downgrade from the 18z, with now just 57% of pert’s showing cold air invade the UK - almost all from the mid-north Midlands northwards, i.e. Lincoln / Staffordshire northwards from T+180 - i.e 15 members of the 30 plus Op and Control, and the ECM is aligned, so too ICON and AI, but after that, the scatter is greater with 50% brining in a return to milder Atlantic conditions, but not the AI, or ECM - whose Op runs remain resolute. Seems all a bit hit and miss - especially for the south. Here is the north-ish of East Anglia, we are on the crack in the map book between cold and less cold uppers, and that probably means cold rain, and maybe a couple of days of sleety stuff. A flake is better than a drop though, and a crunchy frost better than a soggy-fest.

Out of curiosity, what are your criteria for the bit I have highlighted in bold?

GFS Op - the LP on Thu first deepens 965mb. Then it fills and bumbles around the west of Britain until Tue 27th when it drifts to the S France allowing E-lies to develop across Britain Tue 27th. These get cut off as a ridge of HP develops from Norway (1040mb) to Britain Fri 30th. Once this ridge withdraws to N Norway Sun 1st Britain is back to being in the sandwich, albeit with colder air from the SE, not the SW, which this summary started with.

ECM - similar to GFS to begin with, but the LP is less deep and moves off earlier so E-lies are in place by the 26th - and get cut off earlier too, by Wed 28th. But it converges with GFS at the end.

AIFS - London, maxima around 8C now, down to about 2C Fri 30th, rain at the end of the coming week, often damp at other times. Edinburgh, maxima from about 5C now down to 2C but at that stage some rather cold nights too, rain at end of week persisting into weekend.

GEFS - in the S mean temps close to norm to Tue 27th agreed by ens members, after that mean below norm with a fairly wide spread of ens members, op amongst the coldest. Rain in most runs at some time or other, heavy in SW. In the N, the mean dips below norm from from Sat 24th and the majority of ens members support this. Snow row figures low in the south, in the N in the  20s (out of 33) after Mon 26th for that week. 

Including the GFS )z Op and the Control - 17/ 32 Pert’s = actually = 53% - so my crude head Maths were slightly out....