Surely it would be a law of dynamics or whatever. 

https://modeles16.meteociel.fr/modeles/gfs/runs/2026011512/gfsnh-0-156.png?12 

Easterlies can “fail” at about 72 hours out. At the moment the signal is still there for some form of chilly easterly in the last week of January. As others have said it is probably 50/50 and you will get some very cold but also not cold runs in the coming days for that period (in the operational runs at least).

We will see some apocalyptic cold runs for UK standards floating around the Ensembles. 

Important people note that and not expect it

These synoptics are extremely unstable and variations will be high run to run. An easterly can look nailed and within a few days but still end up being a damp cold few days instead.

The ECM Ens are not without interest, with one  cluster shown around the -15 mark as January comes to a close.  

A snowmaking Easterly still looks the less likely scenario, but it's very nice to see the option is being modeled from one set of ens to the next. 

Does anyone above background info on the AI models? Do they receive the same amount of data and what's their verification stats v the traditional models?

Indeed, there was an infamous debacle some years ago when the entire GEFS ensemble set (apart from one lone member maybe?) showed a week-long easterly freeze-up starting at 72-96 hours out. And in the space of one run the whole thing collapsed. 

I think Darren had the charts saved?

I just want this to get to the point where we can all fear 'short waves' 😅

Agree, but these don't look at all solid. 

No, and I don't think they've ever been quite so keen as the GEFS have since the Easterly signal was first picked up.

I guess things will become clearer in a few days... Or perhaps not 😅 

And it certainly beats the usual mid January air of resignation in this forum 👍

I think it's been a brilliant winter for those who enjoy model watching, though maybe somewhat frustrating for those who don't live in Aberdeenshire 😁

"The GEFS mean is one of the coldest forecasts I've seen in recent years going out to T+384" ........ if only somebody would give me a pound for every time I've seen this post in the last 20 years I'd be very rich! 

Quiet often it seems the same people saying it or similar. Wishful thinking or something else 🤷

18Z GFS certainly won’t prove you wrong. That makes 3 in a row where the Atlantic wins. The block barely even puts up a fight on this one. 

I don't have the full chart, but someone put a snip of it in their sig and I copied that. I can't work out a way of posting an image stored on my computer in a post here, but the run was dated Mon 09FEB2009 18z (London). 

I think ideally we'd like to see an op go down the cold route over the coming days. Obviously a volatile situation that isn't easy to model, but concerning nonetheless. 

Hopefully things will look clearer by the early next week 🤞

I think tomorrow's runs and those over the weekend will make for very interesting viewing, as I get the feeling this is still a long way from being settled one way or another.

I think you might be talking about February 2009, Rob.

That month did start with a cold easterly spell which produced snow in quite a few places, and at one point there seemed to be pretty good agreement across the models that it would last for a while. However, one day just before mid-month the ensembles did a volte-face and showed milder weather moving in.

Lots of twists and turns to come (I don’t believe that for a second, but if I don’t post it, someone  will say it)

As soon as I read the above a few days ago my heart leapt knowing full well it had zero chance 

To be fair, it won’t go fully wrong (right actually) until the MetO issue a ten day trend about it happening 

GFS runs today have developed an LP to the North of Scandi towards the end of next week, which moves SE and destabilises the block. The Atlantic then has a free reign to move in. ECM 12z tonight did something similar. 

Noticeable that the AI models (and JMA), which still show the frigid Easterlies, don't develop this system to the same extent.

If tomorrow's ECM and GFS runs continue with the same theme, it could be significant. 

Not ruling out some chilly days here and there with the odd frost I do believe we have seen the coldest the winter will throw at us down here already. Those further North and northeast though might still be in for some more winter weather.

I don't hate "AI", but I *do* hate the hype over it - it's just pattern-matching, a database lookup as things stand. 

It's interesting though, isn't it, how the "AI" models have been so consistent with their modelling of a classic easterly spell. It strongly suggests, IMO, that had we had the current setup in the past few decades we would indeed have ended up with a snowy spell (for many, if not most).

Here you go - the full charts, rather than the animated snipped version I once posted. I only saved these once a day at the time, but the flip did indeed happen in 6 hours!

https://ukwct.org.uk/weather/ens09.png 

https://ukwct.org.uk/weather/ens10.png 

https://ukwct.org.uk/weather/ens11.png