LRD

It's FI so won't happen but those last few frames of the GFS 6z op - blimey. Conditions would be extreme. Storm force winds, heavy rain, snow/blizzards/white-out conditions on high ground Dangerous but fascinating

Agree - that is almost, ALMOST a classic chart. Push everything south by 700-800 miles, including that pesky interfering Azores High, and there is a countrywide snow event

Crystal Palace's home kit

Yeah, I'd say it's about that. Maybe 70-30 It continues deeper into the ensemble run

Damned if they do, damned if they don't I think the Met Office do a terrific job most of the time but they do no right in some people's eyes. Get 8 out of 10 things right and are criticised for the 2. Weird Anyway, another warm op run obviously with 2 distinct clusters setting up. Interesting. Short ensembles:

See where it sits in the ensemble suite but this is a really poor (for cold) run from the 12z. Not even a straw to clutch in the polar profile like there was in the 6z run Met Office don't see prolonged cold going forward but they don't exactly shut the door on the possibility either. Hope the teleconnections give us a cold Xmas. 13 mild Xmas's in a row if this upcoming one turns out that way

Does make you wonder how the media would react to a proper fall of 15, 20 or even 30cm

I'm not an expert but I always look at teleconnections as a forecast too. Just because MJO is predicted to be in a particular state it doesn't necessarily mean it will manifest. And, even if it does, just increases chances of 'something' happening rather than guaranteeing it. The way I've always thought about it is if, for example, the MJO looks to support cold in NW Europe but it doesn't arrive it doesn't mean that micro stuff (shortwaves, spoilers, etc) has blown that away. It means a stronger teleconnective variable has just over-ridden the MJO If teleconnective signals are neutral or weak then, I think, that's where more local influences can take over. But I'm just putting it out there - someone with more knowledge than me can make me right or correct me if I'm wrong

Exactly the point I made earlier but you've put it better. Shortwave this or shortwave that - they're only a drama 'cos the teleconnections and other global stuff has allowed them to cause drama. If the global drivers didn't allow that, they wouldn't. But these shortwaves or spoilers or whatever are not driving (or destroying) a given (cold) pattern like some seem to suggest they can

Even at the end of the very mild op run there were hints in deepest FI of a Scandi high wanting to form.

Short ensembles show that the 6z op was a very warm run. But the trend is clearly up, 850s-wise, next week. With the polar profile throughout the entire run, any mild spell might not last too long

Very mild in a week or so

It didn't slide. Iberian/Euro high incoming But things still looking good at the pole. There'll probably be more cold at some point in Dec. Let's hope it's the snowy variety next time

Or the opportunity was never really there in the first place? Because the set-up wasn't quite right. Is it a good opportunity if a midfielder gets a shot on goal from 30 yards away, which I think this was always the equivalent of. It might fly in but, mostly, it won't. We might get better. clearer chances in the penalty area later in winter if the teleconnections behave themselves

High pressure looking to invade or already over Iberia on many of those clusters at 192+. Need to see that trend disappear

Yes, it's the macro stuff that really drives things. Not the micro-environment low pressure systems/shortwave spoilers. If the macro stuff is flimsy or unsupportive then, yes, shortwaves can have an impact but only cos they're allowed to have an impact by the macro/bigger picture stuff

But even then we saw a cold pattern 1st half of Dec only last year. And what was being progged very rarely looked any better than 2022. So, for some to say that we haven't seen these model developments early in winter since 2010 was hype Had the same in March this year - a 3 day slushy/wet snow fest and we had predictions of the coldest March since God was a boy

You're right. This chilly spell is absolutely nothing out of the ordinary

The impression I get on here sometimes is that it's shortwaves that determine things and make or break patterns of weather. Surely they are just a symptom of bigger picture stuff - teleconnections, SSTs, etc. Not the cause I always thought that shortwave spoilers won't be able to destroy a broad pattern that is set up to support high latitude blocking. And, as the teleconnection experts on here have been saying, this set-up was always a bit flimsy - therefore enabling small areas of low pressure to disrupt it far easier than a scenario where the bigger picture is more solidly set-up for cold. Sometimes we get lucky and shortwaves don't break a flimsy pattern but they usually do In other words: -Bigger picture/jet profile/teleconnections/SSTs/ENSO/etc - the cause of broad conditions -Shortwave(s) behaviour: the symptom That's why Dec 2010 and Mar 2013 were so confidently forecast as the bigger picture stuff was geared towards shortwaves behaving in such a way that enabled cold.

Possibly. The reason I'd favour a scandi high from there is due to the warm air being blown to the west of Scandi and the low over us looking like it could disrupt and other angry lows struggling to make it past the Meridian. The low to the SW of Greenland looks too strong to allow a GH Not worth over-analysing this far out but good to speculate occasionally!

EC 240 could lead to a Scandi high but a long, long way off

GFS and ECM ops remarkably similar at 168 ECM GFS

GFS looks the same at that point and then it did what it did. Not saying the ECM is heading the same way of course

Just had a flick through some ensembles. There are a fair few that build a high into Scandi but we are on the warm side of that block. So, in that sense, the op isn't totally outrageous. It's unlikely, though, of course About a third (maybe slightly more than that) want to bring in Euro heights. Quite strong too

Yep. The op has a little friend but that evolves in a very different way. That member stays cold throughout. Doesn't do what the op does The op has that 1 member following it but I'm calling outlier anyway. Not unexpected Chuckle