Model Output Discussion 17th Dec.2013-12z onwards.

[Captain Shortwave]

I can see how the ECM develops it's pattern this morning, luckily I think it's underestimating the vortex segment over Canada and Greenland, hence that Euro/UK high doesn't really look on. Unfortunately I can't see a quick route to cold either. Hence the slow route is looking the most likely path.

The Arctic high and the two separated lobes of the Polar vortex and both good news. The Siberian one should potentially lead to another strong Pacific ridge. But the models want to elongate the Canadian vortex and push a finger of it through Southern Greenland which is never a good thing.

Possible route to cold - Week one an easing of the stormy conditions, if continuing the unsettled trend. Week 2, this is the crucial week and could be key to how the rest of winter pans out. A strong Pacific ridge causes a response from the Canadian vortex, possibly sending a big chunk towards the UK (another wind-storm perhaps), this clears the Greenland area allowing a ridge to build northwards in the Atlantic to facilitate a northerly followed by and easterly with heights to the north of the UK.

If it's going to turn cold, I feel it's going to be this route. But we need to clear Southern Greenland, the ECM op doesn't look keen this morning. Lets see what happens.

 

Worth noting at present that I feel that any conceivable outcome can't be discounted (Zonal, freezer or just dry and settled).

Edited December 26, 2013 by Captain shortwave

[pdiddy]

BBC Forecaster just said "nothing in our models suggest cold, and the models go out 30 days".  It's a confident call, seemingly.  Relatively tightly bunched 850s trending to average:

 

http://www.wetterzentrale.de/pics/MT8_Aberdeen_ens.png

 

I think the signs of change are there; the arctic high to gradually displace the pv from current position and jet to slip South.

[jvenge]

Hi All,

 

Hope you all had a good Christmas. The large amounts of wine I drank yesterday is lingering a bit this morning.

 

I'm still trying to learn things here and I don't want to start criticising, but it is actually hard to figure out what you lot been by "mild" or "cold". For example, today in my neck of the woods it will struggle to get above 2 degrees today. However, I get the impression you lot don't think this is cold. The weather forecast tells me it will get a little warmer for the weekend, with temps around 7 degrees. So, when you say no signs of cold, are you basically saying no signs of days where it doesn't get above freezing? No sign of prolonged cold (3-4 days or more)? 

 

It seems a lot of people spend time discussing the model outputs but don't actually translate what it would actually equate to in real terms. Again, I'm not going to tell you what you should and shouldn't discuss, but it would be helpful for a little more detail.

[Frosty.]

BBC Forecaster just said "nothing in our models suggest cold, and the models go out 30 days".  It's a confident call, seeminglyh.

It's also not what the met office described yesterday which was for a gradually colder outlook with snow eventually to low levels, at least for the north, and increased frosty nights. Ho hum

[Blizzardof82]

BBC Forecaster just said "nothing in our models suggest cold, and the models go out 30 days".  It's a confident call, seemingly.  Relatively tightly bunched 850s trending to average:

 

http://www.wetterzentrale.de/pics/MT8_Aberdeen_ens.png

 

I think the signs of change are there; the arctic high to gradually displace the pv from current position and jet to slip South.

Forecasters are as fickle as the models

[lorenzo]

RE : Map 4 8-10 day means to compliment your great artwork Nick, hints of Map 3 above in the ECM ensemble suite, and as SK pointed out this is where the ECM has been misleading.

 

 

[Tim Bland]

Perhaps the bbc weather presenter was right? Nothing significantly cold in the models...But does it need to be a significantly colder than average jan of us to see widespread snow? Only a degree or so below average could see occasional snow falls. Significant cold usually = cold & dry. What I think we could see is lots of marginal snow events with accumulations mainly over high ground but not always.

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=288&code=0&mode=2

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=0&mode=1

Edited December 26, 2013 by Tim Bland

[Captain Shortwave]

Day 10 spread from the ECM

Big uncertainty to the Atlantic pattern going forward. Probably caused by how much energy extends from Canada into Southern Greenland.

I'm personally calling a "I don't have a sodding clue" over this. I feel it could go either way.

Edited December 26, 2013 by Captain shortwave

[Frosty.]

Forecasters are as fickle as the models

oh i'm really looking forward to today's MO update to see if they say there is nothing cold showing on their models for the next 30 days, I actually think there is cold potential showing in some of the models we have access to, again it's mogreps which will have more influence on how they see things but I will be surprised if there was plenty of future cold evidence showing on their models yesterday and nothing today.

Edited December 26, 2013 by Frosty.

[stratty]

Perhaps the bbc weather presenter was right? Nothing significantly cold in the models...But does it need to be a significantly colder than average jan of us to see widespread snow? Only a degree or so below average could see occasional snow falls. Significant cold usually = cold & dry. What I think we could see is lots of marginal snow events with accumulations mainly over high ground but not always.http://www.meteociel.fr/modeles/gfse_cartes.php?ech=288&code=0&mode=2http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=0&mode=1

.......i love the way the snow graphic is pixelated in 1cm blocks!  It's liked it can't be ar*ed as it knows it won't happen so far out! lol 

[weatherguy]

Hi All,

 

Hope you all had a good Christmas. The large amounts of wine I drank yesterday is lingering a bit this morning.

 

I'm still trying to learn things here and I don't want to start criticising, but it is actually hard to figure out what you lot been by "mild" or "cold". For example, today in my neck of the woods it will struggle to get above 2 degrees today. However, I get the impression you lot don't think this is cold. The weather forecast tells me it will get a little warmer for the weekend, with temps around 7 degrees. So, when you say no signs of cold, are you basically saying no signs of days where it doesn't get above freezing? No sign of prolonged cold (3-4 days or more)? 

 

It seems a lot of people spend time discussing the model outputs but don't actually translate what it would actually equate to in real terms. Again, I'm not going to tell you what you should and shouldn't discuss, but it would be helpful for a little more detail.

 

Indeed there does seem to be a disconnect on here between cold and "cold"... 

 

I suppose it's because a lot of people looking at the models here are looking for snow and/or extreme cold.  Thus, the netweather definition of cold tends to be "cold enough to snow"...If it isn't cold enough to snow but surface conditions are around 2C, well, it's cold but not "cold"! 

[Frosty.]

The BBC forecaster actually said nothing particularly cold which is rather different to saying nothing cold, there is no sign of the weather settling down and the jet stream is going to remain very strong until well into Jan, so it sounds to me like slightly milder, wet & windy spells separated by colder, showery spells with wintry showers, especially on high ground and occasional frosty nights during the quieter interludes between vigorous atlantic low pressure systems. My definition of particularly cold is sub zero maxima / minima so we still have normal cold weather to look forward to at times for the time being. I would be more concerned about further flooding and stormy winds which are going to continue, on and off for the next 2-3 weeks at least.

Edited December 26, 2013 by Frosty.

[terrier]

Whilst everyone is wondering if it's going to get snowy or not. Susan Powell just been interviewed over the flooding on bbc ness 24 and she has just mentioned that they is very little in the way of cold weather. With us been in this wet mobile pattern right out into mid jan. So if that's from the met office that's good enough for me. And if it is a wet winter so be it nothing we can do about it.

[karyo]

There was a post in the stratosphere thread yesterday which had an extract from the Met Office forecast for January- February- March period. It states that they expect the temperatures to be slightly above average so no big freeze for this winter! The only chink on light was the possibility of a sudden stratospheric warming in February but that's only a possibility and if it has an effect it will be late Feb or March. 

 

January is not looking promising I'm afraid!

 

Karyo

[Mucka]

Yes I know you have, but with very little really consistent and concrete evidence that a change is going to happen from the model output so far, so I would say keep your trumpet handy but don’t blow it just yet, but a great call if you are on the money. Now I’ve just seen Steve’s post re data at Christmas time and it suggests the jury is out in regards impacts on model output, but I would reiterate what I said, that a couple more days of decent output would give me more confidence that real change is coming, because we have certainly seen dodgy output before at this time of year, In regards the ensembles, I have to say I don’t set a great deal of store by them, I find that they are as likely to muddy the water as clear it or point at everywhere and nowhere, I prefer to use an ensemble in my head of resent operational’s, now these do suggest a trend to height rises across the pole and possible movement, split and weakening of the PV that been stuck over Greenland, all good news that at the least may give us a chance of something more wintery. However, as yet they are not really pointing at the kind of patterns that most of us want to see.

 

I think there is concrete evidence regarding a better NH profile, trough sinking into Europe, a weaker Atlantic and better prospects for at least weak blocking first half of Jan - that is all pretty much in the here and now. How that evolves is, of course, up for grabs.

It's all about expectations really. I've always said that it is unlikely we will see the sort of blocking and deep cold people are looking for in the first half of Jan (though that may be possible toward mid month and second half) but chances of snowfall to low levels should be much better as troughs disrupt NW/SE with transient ridges and weak blocking to the North. If that occurs it is case of how much Arctic air we can pull in and far South we can get the pattern as to how far South any snow will fall and that boundary line will of course move North and South, East and West across the UK according to detail that we can't forecast yet. I still expect to see snow falling to low levels though, especially Northern England at times though any accumulations will very likely be transient.

The other possibility is that the weak blocking signal gets blown away as the PV over Canada fragments and moves East, not enough disruption then we will likely get any snow restricted to hills.

 

If we want to see the sort of blocking and deep cold people are looking for then the best option will be an Atlantic ridge forming behind when the PV has been weakened but the possibilities for this come later in the second week of Jan IMO.

The MetO are still calling no cold signal but it wasn't so long ago they were forecasting mild spells, at least the chance of snow falling to low levels has now been recognised somewhat in their 30 day forecast. 

I guess if you are in the South then temperatures will likely come out around average through the first half of Jan but further North will probably be a little below average so in that respect there is no cold signal but that doesn't preclude some cold days with snow falling during the period, more especially in the North.

 

I'm surprised how bullish the MetO have been TBH. They seemed over zealous with their "mild spells" and "low probability of snow falling away from hills" with their 30 day forecasts which only changed that message yesterday and now they seem to be going out of their way to call no cold in Jan more or less with their "No cold and our models go out to 30 days remark", if correctly reported here. I would think they would need a pretty strong signal for the PV to reform and a flatter pattern to return around mid month to be so bullish so that isn't good news but from the information we have there is no signal for a return to the flat West/East zonal and stormy conditions or for the limpet Azores/Euro high giving a more settled mild SW flow, such as we saw through much of this December, to return quickly in January.

 

It looks like staying unsettled but with greater snow risk to lower levels to me (mainly in the North) with the possibility of more prominent blocking forming in the second half of Jan but the weather will do as it pleases in the longer term regardless of what the models, I or even the MetO predict. 

 

This mornings output isn't great but the ensembles are still showing an unsettled but chillier pattern as we head through January.

 

Edited December 26, 2013 by Mucka

[Joe Levy]

There was a post in the stratosphere thread yesterday which had an extract from the Met Office forecast for January- February- March period. It states that they expect the temperatures to be slightly above average so no big freeze for this winter! The only chink on light was the possibility of a sudden stratospheric warming in February but that's only a possibility and if it has an effect it will be late Feb or March. 

 

January is not looking promising I'm afraid!

 

Karyo

January is still a week away which is not exactly short range, and the rest of the Winter and March, well that's obsurdly far away! There is already stratospheric warming scheduled to take place in January - it doesn't have to be sudden to benefit us! The Met Office are as prone to error as any major forecasting organisation so do not write off a period of 3 months on the basis of a long range forecast. The Met Office provides a clear disclaimer explaining about the experimental nature of long range forecasts.

[bluearmy]

The metoffice have mogreps-15. Apart from that, we can see pretty well all they use for the post 10 day period. Not in the same detail as them but certainly enough to know if a statement is reasonable. Without hearing the comments, i couldn't tell you but i can recall occasions in the past few years when the forecasters have stated similar when the extended models were showing a likely path to cold. The forecasters were wrong.

Anyway, nick's maps and snowking's comments are good guidance today. The extended ecm still in the same place as it has been for days. euro trough but what path will the energy to our nw take to get there ?

[Cheshire Freeze]

Whilst everyone is wondering if it's going to get snowy or not. Susan Powell just been interviewed over the flooding on bbc ness 24 and she has just mentioned that they is very little in the way of cold weather. With us been in this wet mobile pattern right out into mid jan. So if that's from the met office that's good enough for me. And if it is a wet winter so be it nothing we can do about it.

 

Like in December 2010 when John Hammond hinted we were locked into a blocked pattern for the winter on BBC News? We all know how the weather shaped up after that.....and it certainly wasn't blocked.

[TSNWK]

Well well. After reading about that update from Susan Powell, it kinda makes me wonder if there is any point viewing the models for a while. We might get a bit of eye candy every so often like yesterday, but it's like watching your team on match of day when they have lost, even if they score first you can't really get excited as you know the final outcome.

[Dancerwithwings]

Well well. After reading about that update from Susan Powell, it kinda makes me wonder if there is any point viewing the models for a while. We might get a bit of eye candy every so often like yesterday, but it's like watching your team on match of day when they have lost, even if they score first you can't really get excited as you know the final outcome.

 

Yes but there's always Extra Time !... Errrrr I think we call that FI

[Mucka]

GFS 06z ensembles

 

NW England

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=235&y=41&run=6&runpara=0&ext=1&type=0

http://www.meteociel.fr/cartes_obs/gens_display.php?x=235&y=41&run=6&runpara=0&type=3&ext=1

 

SE England

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=292&y=133

http://www.meteociel.fr/cartes_obs/gens_display.php?x=292&y=133&run=6&runpara=0&type=3&ext=1

[nick sussex]

RE : Map 4 8-10 day means to compliment your great artwork Nick, hints of Map 3 above in the ECM ensemble suite, and as SK pointed out this is where the ECM has been misleading.

test8.gifeps_z500a_c_exatl_43.pngeps_z500a_c_exatl_47.png

I would agree re the ECM, it's had an obvious bias over the last few years with blocking to the ne and I certainly wouldn't trust it because of that. However in terms of the debate over the UKMO outlook I'm a bit surprised they would make such a confident call that far ahead.

 

They obviously expect the stalemate scenario with map 4, however its a difficult set up for the models because of their issues over trough disruption.

[Mark Bayley]

As i posted yesterday the PV is likely to remain strong, with the current stratospheric conditions, so i see no prolonged cold spell on horizon. Despite that still some indication from the models of the trough pushing into Europe, and the possibility lows undercutting the UK (e.g. FI 6z GFS), with something a little closer to average/colder than. Something to keep an eye on 

Edited December 26, 2013 by Mark Bayley

[mcweather]

Whilst everyone is wondering if it's going to get snowy or not. Susan Powell just been interviewed over the flooding on bbc ness 24 and she has just mentioned that they is very little in the way of cold weather. With us been in this wet mobile pattern right out into mid jan. So if that's from the met office that's good enough for me. And if it is a wet winter so be it nothing we can do about it.

 

 I would be very wary of any forecaster amateur or professional who confidently predicts what the weather will be like in 30 days time.

All that Susan Powell is actually saying is that there looks to be very little in the way of cold weather from what the models are saying TODAY. She cannot speak for what the models might show in a few days time because she doesn't know what they will show.

 

 One can tell by the way the ECM 32 dayer flips around like a fish out of water how quickly indicators can change. By this time next week the models may well start to pick up on a completely different set up. Only time will tell.

[karyo]

January is still a week away which is not exactly short range, and the rest of the Winter and March, well that's obsurdly far away! There is already stratospheric warming scheduled to take place in January - it doesn't have to be sudden to benefit us! The Met Office are as prone to error as any major forecasting organisation so do not write off a period of 3 months on the basis of a long range forecast. The Met Office provides a clear disclaimer explaining about the experimental nature of long range forecasts.

 

People were saying similar things exactly a month ago and December was a write off! The Met Office is confident for a generally mild winter and they have their reasons. I know they can be wrong and they have been on occassion in the past but they have more knowledge than us.

As for the stratospheric warming, it doesn't appear to affect the vortex. I hope this changes but at the moment it is looking unlikely. Go to the GFS stratosphere temperature 30hpa and you'll see what I mean.

 

Karyo