LRD

Well, looking at the models this evening, it looks like my fears are already being realised - a big, bloated Azores high ridging into Europe = no interesting weather for the UK. I realise it might not have a lot of bearing into late November onwards but it is never nice to see at this time of year

I've recently read a theory that, in the last 30 years, global warming has bloated the Azores High and other sub-tropical high pressure systems (the Hadley Cell) way beyond it's usual, historic autumn and winter latitudes. Looking at the models the last week I'd say that it's ready to form in it's autumn/winter/interesting-weather killing position once again. Even in poor summers the SE benefits from the over-inflation of the Azores high and its ridging into France and it is now pretty rare to get truly awful summers in the SE quarter of the UK these days. This is something I'm going to be looking out for this winter. The funny thing is, if the high becomes ridiculously bloated it could end up in and around Greenland, accidentally plunging us into the freezer!

Snow showers, perhaps merging into longer spells of snow for the southern half of the UK. I know it won't look like that at day 10 but I wonder if that ridge of high pressure just sneaking out of Newfoundland and flirting with Greenland wants to hoover up the Scandi High and turn it into a Greenland one? What with the vortex seemingly wanting to move to the Eastern side of the polar field. It's the hope that kills you

Indeed. And that all lends itself to an eventual mid-latitude high. Again...

I think that's a height anomaly chart... not a temperature one

Thanks. Yeah it looks promising for scandi heights but those purples look angry and only a slight move by the vortex towards Europe would surely crush those heights south. Unfortunately. Having said that, I'm sure on the 16 Jan the actual pressure pattern will look very different anyway!

Hope I'm wrong but that vortex (am I right - is the purple area the vortex?) looks fierce. Not sure that high pressure could sustain. Great chart for our corner of the world though. If only Where's IDO gone? Value his contribution and I'd like to hear his view on ECM's output tonight

Even if it all goes pear-shaped on the ECM from now, we have made progress (towards a possible cold outcome) tonight so don't worry too much if 192 onwards doesn't show anything too exciting

Yeah agreed. Not hanging my hat on anything yet

Going back a bit, admittedly, but 2nd half of Jan 2013... UKMO showed cold, the others didn't and it ended up cold. Don't think UKMO have ever showed cold at 6 days in the last 3 winters but I can't back that up obviously

Regardless of stats, anecdotally, it seems to me that UKMO gets more right than wrong in potential cold or knife-edge situations. At no point did UKMO see a cold spell during last week's runs (for this week) while the other two did. I think the real lesson here is unless all 3 of the biggies are in agreement on a potential solution (even with an ECM/UKMO combo), then treat with serious caution (actually treat with serious caution anyway!)

I value all the models but just have a preference for UKMO. Let's remember though, during last week's shenanigans, even in the day 6 range (as far as we can freely see UKMO output) ECM was showing very similar to what the GFS was showing and UKMO was showing something different.

By all means don't get dragged in by it but, last week, GFS and ECM were predicting cold and possible snow this week and this weekend. UKMO never did

If I could only throw all my cold, snowy, frozen eggs into one basket they would be thrown into the UKMO's. It never saw this coming weekend's cold spell-that-won't-verify that the others saw and hopefully, hopefully, it is seeing something of cold substance now which will verify. I'm not the chief programmer of that model or anything and I know I keep banging on about it but, short-range, it is usually the one you want to see showing winter cold

Thank you for confirming. I thought I was going mad! ECM - cold, dry and boring. Something setting up at Day 10 but best not to get to involved in that at this stage

Yep, the red line is the 81-10 mean on there too Black line - ensemble average Green - the op I can't see the word 'moyenne' on this chart. Are we talking about the same graph? That's it on this as it's cluttering up the thread but no way is that red line on the above chart for the 31 Dec 2016 12z the ensemble mean. Sorry but it just isn't

Sorry pal. That's wrong. The thick black line is the ensemble mean. The red line the 81-10 mean. Look at the key bottom left

Gawd knows. But that's what seems to happen! An out-of-the-ordinary spell is predicted, then is usually not retrieved once the idea is dropped

You're looking at the red 1981-2010 mean, surely? I'm looking at the thick black line. That's the ensemble mean

Because, unfortunately, that hardly ever happens. I can only think of one example (in winter) and I've mentioned that example too many times on here already! Once the models revert back to climatology it stays on that road. My perception is that happens more so in winter than summer but I could be wrong

In the space of 24 hours (or even less) the 850 temps have gone from a mean sitting at just below the -5 mark to now being just above the 0 mark - for the period around 6-8 January. Sheesh, disappointing isn't the word. Never flips the other way in winter does it?

Even though it's been a bad day for those actually wanting some winter weather in winter (shock, horror) the fact that UKMO is showing something at 144 means there shouldn't be a complete write off of the cold. Have to say, though, that the direction of movement today is concerning. Once a cold spell is dropped in the model suites it rarely comes back. Jan 2013 being one example where it did (and guess who spotted that better than ECM and GFS and every other model - yes, the mighty UKMO!)

The UKMO model has been superb during the last 48 hours or so. Consistent in its outlook (although it seems to have taken a step towards cold tonight - possibly temporary). It really is the short term King. It seems the longer term models have failed this winter but I don't see the point of people calling for them to be scrapped. They need to continue to evolve, pushing met science as far as we possibly can

Great explanation and this really does make you think 'what can go wrong, will go wrong' for UK cold and snow

I always though the Tripole that I described encouraged a negative NAO Have I read this wrong then? http://www.metoffice.gov.uk/learning/learn-about-the-weather/north-atlantic-oscillation