Model Output Discussion - Christmas week and beyond

[mulzy]

Just now, tight isobar said:

As the most ardened coldie there is..— defeat is almost upon us!! The triangle of doom ramps up...

The writing has been on the wall for a few days.  Relying on the GFS was sheer desperation.

Straws left:  the MO medium ranger and weeks 5 and 6 from the Euro sub-seasonal.

[Daniel*]

Boxing Day on ECM 12z pretty grim for far south just slightly too marginal to deliver a wintry outcome.

[Battleground Snow]

I think we've seen enough from the ecm, Gfs and gem at 120-168 to say things are still very uncertain and minor adjustments are enough to change the whole pattern.

Every run at 144 seems to be totally different from the models, this is telling in itself. The monster USA storm/ cold pool is only just developing 

No doubt the flatter pattern is favoured past 168, but with even the met office citing very low confidence, you can't bet against something better for cold fans.

Also the ec46 is still bullish about keeping the AO negative well into January (this may change on Thursday update)

[Stuie]

ECM is like maybe pottery with the cold...

This looks like rubbish so you know what, lets clump it all together and start again.

 

[Cymro]

15 minutes ago, January Snowstorm said:

Am reading a lot about the uncertainty across all the models. Here's what I think:

- The gfs likely called Christmas correctly, ie cold with some wintry stuff up North. The other models have now largely picked up this idea.

- The gfs persisting with heights over Greenland long term looks incorrect. Why? Because all the other models largely agree on a zonal type setting up.

For me the way fwd is very clear, a transient cold spell for a couple of days coinciding with Xmas day which then reverts to more normal Atlantic stuff. I'm 100% the gfs will back down

You are a brave man! 100% at your peril! 

[blizzard81]

It really tickles me how some people on here are so absolute and rigid in their opinions on here at the moment. The models are all over the place - and yes... That includes the ecm (see my earlier post). However, some on here are so certain they know what's down the line. Really? When the OP runs are flip flopping like a jelly fish on a trampoline we should all remain open minded for the time being. 

[LRD]

ECM 240 and back to the familiar, old winter pattern we all know and 'love'

This is what ECM's extended was predicting only 23 hours ago for next week

Assuming the ECM and other trends for next week are correct, at least EC46 is half right I s'pse - it's got the SE height anomaly correct

[TEITS]

The combination of the varying operational outputs, ensemble scatter, bombogenesis that is going to occur in the USA, means im sitting on the fence for the xmas period. We have taken a step backwards but this isn't enough for me to throw in the towel just yet.

[Ladyofthestorm]

The teleconnections are not exactly screaming mild Atlantic either. AO staying neg and the NAO negative to neutral.  Not exactly the Atlantic flip.  

Yes chances of a white Christmas for the south of UK is very slim , but further north every  possibility .

 

Looking ahead anplication of that problematic deep low, but look how it backtracks  and moves west over the Atlantic. 

So no clues. As yet. The ensembles are still anyone's guess even mid term. 

 

Certainly don't put away the sledges just yet. 

[Ladyofthestorm]

10 minutes ago, Cymro said:

You are a brave man! 100% at your peril!

Agreed, I think the GFS is closer in resolution than the EC. 

[CoventryWeather]

10 minutes ago, LRD said:

ECM 240 and back to the familiar, old winter pattern we all know and 'love'

This is what ECM's extended was predicting only 23 hours ago for next week

Assuming the ECM and other trends for next week are correct, at least EC46 is half right I s'pse - it's got the SE height anomaly correct

I'm an amateur, so correct me if I'm wrong. But is the EC46 often unreliable in the extended? 

Anyways, I believe in a flatter pattern next week. Some colder drier intervals, then milder and windier. Typical Atlantic Zonal. 

[Bricriu]

2 minutes ago, blizzard81 said:

It really tickles me how some people on here are so absolute and rigid in their opinions on here at the moment. The models are all over the place - and yes... That includes the ecm (see my earlier post). However, some on here are so certain they know what's down the line. Really? When the OP runs are flip flopping like a jelly fish on a trampoline we should all remain open minded for the time being. 

I would agree, but at the same time no model is signalling a prolonged cold spell, just transient cold. This is not enough to satisfy many here, they want a deep freeze. I think we can safely assume at this stage there is not going to be a sudden flip to a prolonged cold outlook within the next 48 hours.  The broad theme over the last few days, despite model volatility, is that any cold and snow is most likely in Scotland and parts of Northern England over the Christmas period. So for a lot of posters who live  further south that's of little interest to them either. 

[Hotspur62]

Just read through 15 pages and it does seem we have stepped backwards from a cold perspective re Xmas day and Boxing Day.Still lots of uncertainty but 2 things stand out for me.The Euro heights are just too strong and I think that over the last 20 years they seem to have crept a couple hundred miles northwards compared to where they used to be(probably a result of CC).The second factor is how the storm in US performs and if it manages to send enough WAA into Greenland.36 hours ago that looked promising from a GFS perspective but got no support from any other model.Now run by run ,even the GFS is dropping that idea.Conclusion for me Scotland,NI AND Some parts of Northern England still in with a chance of a white Xmas.The rest of us really would need a Xmas miracle for a white one.What happens after that is anyones guess and well above what knowledge I have but if I had a punt I would just say pretty average fare for late December as JH and Mushy use the NOAA 8-14 day charts suggested yesterday I believe.

[LRD]

Just now, CoventryWeather said:

I'm an amateur, so correct me if I'm wrong. But is the EC46 often unreliable in the extended? 

Anyways, I believe in a flatter pattern next week. Some colder drier intervals, then milder and windier. Typical Atlantic Zonal. 

Like any longer range model, it will have weaknesses but EC46 is usually ok at predicting 1 or 2 weeks ahead. Next week is week 2 of course. Obviously, it'll get less accurate the longer we try and look out to

If the low pressure to the north and NW and high pressure to the south regime, that has been well advertised throughout today by most models, verifies then we can say that EC46 has failed at week 2. Of course by Thursday the EC46 forecast might completely change

[weathercold]

It’s evident the tide has turned towards less cold for Xmas and beyond. Those Iberian heights have really ruined what could have been a much more exciting outcome for coldies. 
we are realistically looking at mild temps nationwide with an outside chance of something colder in Scotland. Beyond that milder Atlantic driven weather into the new year with a +NAO setting up.

 

Edited December 20, 2022 by weathercold

[Stuie]

To be honest the NAO is a mess but clustering increasing for negative.

[ribster]

10 minutes ago, Bricriu said:

I would agree, but at the same time no model is signalling a prolonged cold spell, just transient cold. This is not enough to satisfy many here, they want a deep freeze. I think we can safely assume at this stage there is not going to be a sudden flip to a prolonged cold outlook within the next 48 hours.  The broad theme over the last few days, despite model volatility, is that any cold and snow is most likely in Scotland and parts of Northern England over the Christmas period. So for a lot of posters who live  further south that's of little interest to them either. 

So you keep saying, but please don't presume to speak for the rest of us. 'Seasonal' will do, had a great first 2 week of winter, and it's certainly not looking blowtorch by any stretch.

[Derecho]

6 minutes ago, Stuie W said:

To be honest the NAO is a mess but clustering increasing for negative.

They have a different definition of the NAO in the US. I can imagine if there was a graph for the definition most relevant for the UK (Gibraltar - Reykjavik index)  that graph would be a bit different....

[Bricriu]

3 minutes ago, ribster said:

So you keep saying, but please don't presume to speak for the rest of us. 'Seasonal' will do, had a great first 2 week of winter, and it's certainly not looking blowtorch by any stretch 

Seasonal/brief snow opportunities will do me too. I will take snow at any time. I was not trying to speak for everyone, just acknowledging that a lot of people on here want a bit more than something seasonal. 

[nick sussex]

Not sure I get the love for the GFS .

It has a high over Greenland which doesn’t produce anything. Low pressure to the south hangs around whilst the cold by passes the UK and is just a very frustrating set up .

The ECM drops the more amplified mid West troughing which could have held some interest down stream by directing more energy se wards  day 6 onwards .

Overall after a lot of drama the final chapter failed to deliver the exciting ending many hoped for .

There’s just about enough time for changes , let’s hope the models suddenly haven’t found consistency because tonight’s outputs can be summed up in three letters ,meh ! 

 

Edited December 20, 2022 by nick sussex

[Stuie]

2 minutes ago, Quicksilver1989 said:

They have a different definition of the NAO in the US. I can imagine if there was a graph for the definition most relevant for the UK (Gibraltar - Reykjavik index)  that graph would be a bit different....

Isn`t that the AO? Thought the NAO covered, erm us? (Not US)

Edited December 20, 2022 by Stuie W

[LRD]

850's-wise, the ECM op was representative despite being one of the colder runs on the 27th and 28th

Intrigued as to what the Met Office are seeing. If it wasn't for their last couple of updates, I'd be taking a break from this hobby for a fortnight. If the Met Office flip to a milder outlook, that will probably be me until 2023

[Don]

49 minutes ago, TSNWK said:

Precisely this. We might get a small tactical waft of cold.  But thr broadscale is setting up positive nao for next few weeks. 

What concerns me is around New Year, winter often (although not always!) tends to settle into it's overall pattern be it mild or cold and with no sign of a SSW, knowing what has happened in recent winters once the trop and strat couple, there is little suggestion to me that January at least and quite possibly February will be much different to last winter?!  This may be a sweeping post and fair enough if people think that, but that's how I see things now.  The Met Office outlook does give me hope but I suspect they will back track very soon, if the models continue as they are.

[Gowon]

Just now, nick sussex said:

Not sure I get the love for the GFS .

It has a high over Greenland which doesn’t produce anything. Low pressure to the south hangs around whilst the cold by passes the UK and is just a very frustrating set up .

The ECM drops the more amplified mid West troughing which could have held some interest down stream by directing more energy se wards  day 6 onwards .

Overall after a lot of drama the final chapter failed to deliver the exciting ending many hoped for .

There’s just about enough time for changes , let’s hope the models suddenly haven’t found consistency because tonight’s outputs can be summed up in three words meh ! 

 

That's one word.

[Derecho]

Just now, Stuie W said:

Isn`t that the AO? Thought the NAO covered, erm us? (Not US)

There's different definitions of the NAO confusingly, there's the Azores - Reykjavik SLP gradient, Gibraltar - SLP gradient and more complicated functions. 

The Azores - Reykjavik SLP gradient I think is often used most by the US, however if we have a low over the Azores and a high over Spain it isn't a great metric. The Gibraltar - Reykjavik gradient is better due to it being more closely connected to what goes on in the UK.