I can’t remember which year saw the most almighty tits up scenario? That one where the models suddenly dropped a major cold spell at +48? If I recall, the EURO op had never shown the majority solution. Just like now.

I can’t remember when that was, but I do remember it. This place was like a wake.

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Gefs have watered down the potential cold snap on the midnight..lowest mean sits at around -7c (my locale)..but its duration is shortening..some ens seem to suggest only a cooler spell..hazard a guess which way this will play in the coming days

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I can’t remember which year saw the most almighty tits up scenario? That one where the models suddenly dropped a major cold spell at +48? If I recall, the EURO op had never shown the majority solution. Just like now.

Each scenario is different and perhaps things will go wrong but that is a much less favoured option currently. Were the ensemble data backing the op run in the scenario you refer to? Did the op run flip from one scenario to another, none of which were supported by its own ensembles?

Marco in contrast here the duration and intensity of cold has actually increased here on the 00z suite. It will be hard to maintain that on future sets for here I think.

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TBH if the response is "it always goes wrong", it makes me wonder what the point of anyone posting on the model thread is. We're discussing what the models show, not what "sod's law" or perceived biases may show.

I would just ask one thing of those who think that one (and just this one, for some reason) ECM op run means the ensembles across the major models are weong...

And that is, on what scientific basis are they wrong? Explain why, don't just say "'cos", which is effectively what the posters above are doing. Explain what you expect to happen instead...

 

I made the mistake of looking at the comments here - and the number of posts - before looking at the charts.

TBH I’m struggling to understand the negativity. In the reliable timeframe it looks fine. One of my personal benchmarks is what the UKMO charts are showing because they usually seem to have more realism in their evolution. The 00z run was fine - and backed up elsewhere.

To my surprise the GFS v16 still looks solid further out into week 2. I’d like to know what’s happening to cause the ECM op to deliver so much more inconsistency in the last couple of days. Just the inconsistency throws up a question mark - but the mean at Day 7 shows an easterly.

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This is getting quite amusing now!

Yes, the ensembles will flip because the ECM op is a mild one. Wow.

Of course, they didn't flip after yesterday's 12z ECM (which was also a mild one), or the one before that, but this time it's gauranteed they will.

PS, got the lottery numbers for the "must be won" jackpot this Wednessday?

 

But if he keeps saying the same thing, he’s bound to be right on one occasion, 🤣, law of averages etc.

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TBH if the response is "it always goes wrong", it makes me wonder what the point of anyone posting on the model thread is. We're discussing what the models show, not what "sod's law" or perceived biases may show.

I would just ask one thing of those who think that one (and just this one, for some reason) ECM op run means the ensembles across the major models are weong...

And that is, on what scientific basis are they wrong? Explain why, don't just say "'cos", which is effectively what the posters above are doing. Explain what you expect to happen instead...

 

Darren, even I remain hopeful of a cold spell this time. Yes there are some concerns that the ECM Operational is not currently playing ball, but the Ensemble mean remains very encouraging, and that coupled with the other big three leaves cause for optimism. I am not anticipating a major freeze up, but I am anticipating a decent cold spell in February, lasting perhaps a week.

I don't quite get why the ECM Op has been consistently off compared with its Ensembles, but I don't think that means it'll be right. As usual, I would expected a blended solution at T+0 and on this occasion, that may be perfect the majority of us.

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They will on the 12zs, just wait. We all know how this story plays out. We've been through it so many times

Can I have a piece of that crystal ball you use - it might come in useful.

Darren’s analysis is sound logic. The reason the ensemble system was introduced was to smooth the digital nature of relying on one solution when we all know how sensitive the atmosphere is to very small changes in starting conditions.

My own very rough system for the ‘overall view’ of cross model agreement (let’s call it XMAG as CMA is used) at 120hrs relies on the operationals because it’s easier to assess. For forecasting detail at 5 or more days I use ensemble data.

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Gefs have watered down the potential cold snap on the midnight..lowest mean sits at around -7c (my locale)..but its duration is shortening..some ens seem to suggest only a cooler spell..hazard a guess which way this will play in the coming days

And that's the outcome I'm expecting now. A shorter cold snap in the South. Scotland will probably be the place for extended severe cold.

I think it's good that the GFS and ECM Ops runs have gone mild as it shows what could go wrong with some very mild air close to the south. As to whether the Ops runs are indicative of a trend or will remain as outliers is another matter. 

It's making for a riveting watch whatever the outcome. 

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I am a bit more interested this morning. In the vast majority of cases you won't get proper model agreement at a week out, especially in winter.

Darren talking a lot of sense this morning and I think that currently there is an 80% chance of a cold snap/spell and 20% of it going tits up. The chance of heavy snow in the south east is probably 20%.

That's pretty good in terms of where we usually are in winter. Patience grasshopper 

 

Why were they not yesterday after the milder 00z ECM op run? Your point is guesswork and directly in opposition of almost all current evidence. 

To clarify, are you dismissing the ECM ensemble suite? If so on what grounds (beyond psychological ones)?

Yes this view is against the vast majority of evidence and you would think, probability but Doc you've been around long enough to know what so often happens. Dec 2012 imploded at a closer timeframe than this.

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Yes this view is against the vast majority of evidence and you would think, probability but Doc you've been around long enough to know what so often happens. Dec 2012 imploded at a closer timeframe than this.

Was that the T+48 Pete Tong? It was the biggest communal wrist slashing event in history. 

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Yes this view is against the vast majority of evidence and you would think, probability but Doc you've been around long enough to know what so often happens. Dec 2012 imploded at a closer timeframe than this.

Trust me, I have been around long enough to know it could happen, it is just not the most likely scenario based on current evidence. If or when the consensus and data shift I will acknowledge that. Nothing is “nailed on” and rarely is in the U.K. until it has more or less started.

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Taking the current model output, there is good support for a cold snap/spell. It is still quite far out so of course much switching can take place, but that is always a risk when you are assessing complex model output at 7-10 days range. As others keep saying, look to the ensembles. Regarding other failed easterlies, I add my experience of looking out the window. In my experience, a cold run up like we have now is a promising sign (snow from previous events has not yet completely cleared) and temperatures are again falling and frosts getting harder. All promising signs. Be patient, be hopeful, but don’t get upset if it flops. There are more important things going on in the world, especially at present - just read any newspaper to see that.

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We need to read the story and not the headlines. All ens are going for a cold snap/spell. If the headline is right then so be it, but let’s read the story before coming to our daily or 6 hourly conclusions.

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From all I that I can see, it seems to me the nub of the issue is that the majority of the main models want to move this coming weeks' LP to the south eventually whereas the ECM 00z op run seems to keep it in place over the UK while gradually filling.It could yet turn out to be the case that the ECM are proved to be correct and the other op runs and the ensembles are proved wrong. However, as had been noted above the ECM ops seem to be out on something of a limb just now.

For me, and as its often said, more runs are needed. ECM is regarded by many as the best model or certainly one of them, but that doesn't mean to say it is always correct without fail and I have seen occasions in the past when it has gone against the other op runs but has then come on board later. I seem to recall that during the lead-up to the Beast from the East at the end of Feb 2018, the ECM ops were all over the place for a while, but then that was true of the other models as well.

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Was that the T+48 Pete Tong? It was the biggest communal wrist slashing event in history. 

I think it was more like T72-96, even the Irish Met had forecast snow moving East to West in the 4/5 day period. Then a GFS 18Z popped up with a little shortwave developing way to the North of the UK. Within 12 hours it had all imploded and by the end of the week we were back in zonality and temps in the teens.

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We need to read the story and not the headlines. All ens are going for a cold snap/spell. If the headline is right then so be it, but let’s read the story before coming to our daily or 6 hourly conclusions.

I've been consistent in my conclusion for the past four days! But I would be dellighted to be proved wrong... truly delighted.

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From all I that I can see, it seems to me the nub of the issue is that the majority of the main models want to move this coming weeks' LP to the south eventually whereas the ECM 00z op run seems to keep it in place over the UK while gradually filling.It could yet turn out to be the case that the ECM are proved to be correct and the other op runs and the ensembles are proved wrong. However, as had been noted above the ECM ops seem to be out on something of a limb just now.

For me, and as its often said, more runs are needed. ECM is regarded by many as the best model or certainly one of them, but that doesn't mean to say it is always correct without fail and I have seen occasions in the past when it has gone against the other op runs but has then come on board later. I seem to recall that during the lead-up to the Beast from the East at the end of Feb 2018, the ECM ops were all over the place for a while, but then that was true of the other models as well.

Initially they were but we ended up with CMA from the big 3 at T144 and the big two that go further agreed the set-up at T192.

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Dec 2012 imploded at a closer timeframe than this.

Yes, it did:

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=5&mois=12&annee=2012&heure=0&archive=1&mode=0&ech=6&runpara=0&carte=1

That's the archive of the GFS charts from the time. It was dependent on the Siberian high migrating westwards enough to link with the Azores High, which in the event didn't happen. Instead, the Atlantic fired up enough to stop the link, meaning we ended up with mush.

The difference this time is that we've had two reversals in the stratosphere, the third starting imminently, so there's less emphasis on westwards momentum aloft. In 2012 there had been no reversals and a warming was just starting - but as you'll know from looking at the charts, that implies a strong vortex to our west or NW.

https://www.netweather.tv/forum/topic/74587-stratosphere-temperature-watch-20122013/page/45/

(A link to the stratospheric discussions at the time).

So - despite the models gunning for some westwards movement, linking us to that Siberian High, the stratosphere was completely against it - like pushing a boulder up a mountain.

This time at least we have conditions aloft in a much more conducive state.

None of this precludes this current cross-model agreement (again, ensembles) from being wrong, it may very well be, but it is a different set up entirely to what we saw in 2012.

Time will tell!

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This puzzles me. We have the coldest set of GEFS ensembles of the past 17 runs (and indeed longer than that). We have EPS which has been lowering the means for the past few runs too, now showing a solid signal for decent cold for a few days. And even GEM, which in my experience is usually the least enthusiastic in terms of ensemble cold, is on board.

It could still go tits up, of course, but there's not much I can objectively see to say that's likely at the moment.

I’m curious how you are defining that bold part, because just looking by eye the 0Z set is less cold than any of yesterday’s, in terms of the mean. 

Colder in terms of the number of members that reach -10C maybe, but the majority only dip down that far for a short time. Compare to yesterday’s 0Z that had a clear cold cluster lasting about 5 days. Now you can barely see the dip because of the spaghetti. 

I find it very hard to share any optimism this morning. A brief two-day waft of -10C air is pretty poor compared to what yesterday morning was showing. 

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