17 show what though? That’s what I’m asking, not the number, rather the criteria you use for “cold” to “invade the UK”. Is it the -10°C isotherm or -5°C at t850hPa? Is it for anywhere in the UK or one specific location?

The ECM suite is I think largely unchanged, maybe with a bit more mild stuff at times but still a robust signal for chilly to cold air. 

MOGREPS is also reasonable with a colder signal - I think there's 6 with -5 850s right at the end down here. 

Ops wise GFS is cold mid to long term, ECM is cold in the mid to longer term, GEM uninteresting from a cold POV with the Atlantic having too much grunt for the block to influence us. Of the pattern matchers ECM is cold, GFS less so although ends with a chilly HP centred to the SE of the UK. 

So broadly as you were but with a slight caveat that GEFS are suggesting a greater chance of the Atlantic having more grunt albeit not the most likely scenario as it stands. The next couple of days should solidify things one way or the other hopefully although given the pattern it wouldn't surprise me if we continue to wobble between Atlantic/blocking for a bit longer or end up with a mix of the 2. 

In this run -10 uppers onto east coast next Sunday and widely on Monday Tuesday.  Pity it's waaay off.

https://www.meteociel.fr/modeles/gfse_cartes.php?&ech=180&mode=0&carte=1 

Exactly. It would be nice to see the general output up to next Sunday aligning with the GFS 6z Op. Then be concerned with its continuance later.

very few of the GEFS keep the cold going beyond day 10.  

EC 06z out to 144 looks wet and cold rain for the south

This is looking like a total bust, maybe a few days of deep cold in Scotland at best and for Aberdeen usual lake effect snow for Doc.   The boys on the other channel are doing their best to sugar coat, but its not working and they know it

Usual lake effect snow? From an easterly. That’s a laugh. Perhaps from a northerly, but that’s not what is modelled. The ECM 06z only goes out to day 6 which is really before the cold air is due to come in.

If the shorter range output does not get there then we will be looking at the next chance of cold. For here we probably would do better under cold polar maritime air from the NW which has been the case over the last 13 years. (Thunder snow). Current output overall still makes Easterly Cold a possibility.

Overall things could still go either way with anything from the Atlantic pushing through without any real cold (a less likely option IMO) to a prolonged cold blast from the east. Statistically, if nothing else, somewhere in between is most likely, but there is avery wide scatter options, unsurprisingly given the synoptics.

With the US going into a severe cold spell. I just feel too much energy will be flowing through the Atlantic

Looking at models, the LPs aren't undercutting the high as much and leaving us cold and chilly as opposed to severely cold 

With-5 850s, snow will always be very marginal for the vast majority. 

As always, people looking for the end of the cold spell, 7 days before it starts. 

Models have signalled cold weather at the end of the month for a fair few days now on a regular basis

Lots of posts. Looking for the BFTE scenario and that's always been very unlikely, members of models will throw out eye watering BFTE but they will not be heavily supported 

It's rare to get a full bloodied BFTE, it's been rare since records began, it was more frequent than it is now but its never been a frequent occurance in the UK.

It's not like the UK had a famous easterly every winter in the 60s and 80s

Our last one was 8 years ago which in context is pretty 'recent' 

Our last sub zero CET was 15 years ago which again in the context of sub zero months is very recent. Sub zero months happen like every 30-40 years 

Aside from the first half of December, it's been average or slightly below for most 

Shorter range I was implying more early medium range around next weekend. The longer range probabilities vary greatly as is expected.

Best chance of an old school cold spell at a good time...feels 1986ish.....the models can pick up trends but useless at forecasting weather they are not used to...

I predicted this prediction at the start of the week. Next week will it be the first week of February or the second week of February! 🙂 Can't have constant slippage. I suspect the turning point will be around January 24th still, then we will know.

I've consistently said the end of January and the first half of Feb. I know some people were talking about this weekend as the start, but that never looked likely to me.

This weekend has never really looked likely IMO. I feel amongst all the twists and turns the timescale has been quite steady as the last week in January. The easterly component was always likely before then (mainly in the form of SSEly) but that was never going to be cold. Things should (maybe!) become a bit clearer for the post 25th period in the next 2-3 days.

The 12Z updates are underway. Here's the ICON-G at t+180.

If that was on it's more usual trajectory aimed at the UK it'd be a far less interesting spell of model watching. 

I’m not paying too much attention to the specifics of any one individual GFS op run (even if it is as wintey as the 12z). Overall the 12z output so far strengthens the colder easterly theme from next weekend.