[Model Output Discussion 29th December - Into mid-Winter.]

ECM out to 168  and it's more of a waft than a beasterly

[Model Output Discussion 29th December - Into mid-Winter.]

Well when the ECM raised the possibility of an move to an  Easterly late last week I raised one eyebrow now I have raised the other one as well. The interesting thing looking down the line from tonights 12z op is that in its latter stages it shows how the cold could become locked in and drive the jet south . Shades of 47 in the final few frames.

[Model Output Discussion 29th December - Into mid-Winter.]

Superb post Tamara. It should be remembered that any synoptic output that we can view is governed by the interplay of the various global and regional parameters and drivers (MJO QBO Tropical convection and many others)  Longer range forecasting is necessarily based on trying to work out what weighting to give these various players in any given situation or as shown last year will one be so dominant as to negate any kind of weighting given to others.

Those who try as you gp and others do to understand these and give some kind of guidance as to the POSSIBLE  broadbrush synoptic outcomes should not be derided or put into some kind of us and them situation because that lowers the level of the debate in this often brilliant thread to a level unworthy of us all.

It is all about learning  and hopefully learning together so that our understanding can help us recognise which synoptic developments to take seriously and which not to, thus eliminating a lot of stress each winter.

 

 

[Model Output Discussion 29th December - Into mid-Winter.]

So yet again the models tease us first flashing us a Scandinavia high then whisking it away.. It seems that some kind of cold northwest or northerly outbreak is reasonably nailed on although how potent is still open to question. Beyond that as IF has pointed out is anyone's guess with low confidence in any option whilst such wild operational swings occur. More than ever a case of wait and see. Hopefully we'll be pleasantly surprised but after many years model watching I wouldn't,t count on it.

[Model Output Discussion 29th December - Into mid-Winter.]

My eyebrow is somewhat raised by tonights 12 ecm although I will be happier to see that exact development inside the 120 mark then I might raise my other eyebrow as well.

Even allowing for Tamara's cautionary tale of things unconducive  to prolonged  cold and snow . If we were able to squeeze a cold and snowy week out of this otherwise rather boring (so far at least) winter a lot of us on here would be pretty happy.

[Model Output Discussion 29th December - Into mid-Winter.]

Afraid to say I remain far from convinced by the midweek model madness.  Same thing happened a week ago only for major backtracking away from the coldest options to occur on the Thursday. Something both the gefs op and control seem to doing again this morning.  As with any stellar charts that come along Unless they'come within 120 hours then treat them for what they. Winter porn and nothing more.

[Model Output Discussion 29th December - Into mid-Winter.]

GFS 12Z actually has sub -5 850,s further south at 174 than the 06z did.

[Model Output Discussion 29th December - Into mid-Winter.]

I know it can be difficult to manage expectations after a stellar run like the 06ZGFS and had it come completely out of the blue I wouldn't give it any credence at all but the truth is that it hasn't there have been a growing number of GEFS ensemble runs since xmas showing similar evolutions to that which the 06z has shown. perhaps another  thing to hold onto as well is that even a watered down version of the 06Z would still deliver what many on here are hoping to see this winter.

 

[Model output discussion - 5th December 2016 - Into Winter we go]

Unlike last year With none of the atmospheric drivers running having a big enough effect over and above any of the others. This winter more than any other it is completely pointless looking beyond seven days. I think we will see some genuinely wintry weather but it pop unexpectedly up in short time frame

[Model output discussion - 5th December 2016 - Into Winter we go]

Well the gefs and ecm seem to still have plenty of Xmas spirit this morning.

merry Christmas to all my fellow snows searchers, yes even Knocker and Sid. I have a feeling Sid will want to wrap up his Christmas nuts come the new year

[Model output discussion - 5th December 2016 - Into Winter we go]

Just thought  I'd check out the 18z before going to bed. Looks to me like. Santa,s already been. Happy Xmas everyone.

[Model output discussion - 5th December 2016 - Into Winter we go]

Is that  the sound of toys being picked up and put back in prams I can hear.

Just when Christmas was starting to look a bit dull model wise the ECM GEM and even the GFS try their best to deliver a nice present

[Model output discussion - 5th December 2016 - Into Winter we go]

1 minute ago, CreweCold said:

The Atlantic isn't blocked though? It's roaring away 1000 miles N of us!

We need to be on the N side of the jet, not stuck on its southern side under a dome of warm uppers!

Yes Crewe we know that but Iceberg is talking about the potential to move on from that point as per some of the gefs

[Model output discussion - 5th December 2016 - Into Winter we go]

23 minutes ago, Ali1977 said:

Finally after a week of dross the ENS are really starting to look up in FI, Some real good charts among them with plenty showing the Atlantic high ridging north towards Greenland. 

Yes rather like happened at the beginning of Dec after after the meto contingency forecast went for cold and blocked and the longer nwp went for mild now the update has gone for basically mild the longer term gefs at least start to trend chillier and blocked. One should remember that Ian F did state at the start of his posts last night that there was very low confidence in the on going monthly and seasonal outputs so writing off winter on the basis of something even the professionals have little confidence in seems a tad premature to  me.

[Model output discussion - 5th December 2016 - Into Winter we go]

2 hours ago, fergieweather said:

Well, very low confidence...!! As expected.

We will see whether ECMWF Monthly this evening keeps banging the blocked drum, or switches and offers the much more mixed signals of GloSea5 (slowly progressive, some blocking, but ensembles unconvincing re ultimate outcome). Dominant signal for remainder of winter (albeit as previously discussed, a divergence in ECMWF & GloSea5 output) is for broadly +ve avg temps (some colder phases possible); +ve NAO (mostly, with possible exception part of Jan) and SPV remaining stronger now. Broad GloSea5 pattern ultimately favours high pressure to S of UK, helping perhaps to keep things drier overall but there's equal probabilistic weighting on +ve/-ve PPN anomalies. December Contingency Planners doc offers further context.

 

THankyou again for your input Ian. The way I see it we unless the ecmwf monthly backs glosea5 tonight we will have the two best lrf tools in the world going in somewhat different directions , yet presumably from very similar initial data. I think what people need to understand is that both of these systems are still to a certain extent experimental  and this is perhaps not made enough of when the the likes of John Hammond do their presentations on the BBC website.. There is no doubt now that the December part of the forecast is completely blown. Yes some may argue that there was blocking but when you go out of your way to say that the blocking will be in a position to bring more easterly or northerly outbreaks with an increased risk of ice and snow and in fact the blocking brings you a mild Dec running some 2.c above normal then  one has to see it for what it is. This is not to attack he Meto office or Ian or John Hammond in any way because I have the utmost respect for the organisation and those that work in it .THe meto and ecmwf are least trying to push the science forward. But just to say that we are nowhere near where we need to be yet to make consistently accurate seasonal forecasts..

[Model output discussion - 5th December 2016 - Into Winter we go]

3 hours ago, Tamara said:

One final repeat (I promise) of the misnomer about longer range signals that continues to persist despite the attempts to correct these and give true perspective

The risk of low angular momentum phase (adding up to a stronger and flatter northern branch of the jet, steepened gradient due to cold air coming out of Canadian arctic and consequent cyclogenesis threat ) was flagged over 3 weeks previously at a time when the consensus modelling gave good support to a cold blocked evolution through most of December.

We have seen a lot of blocking, but it has not been the variety perhaps anticipated and hoped for as autumn was coming to a close.

That unpopular phase possibility, that seemed a long way and, understandably, rather unlikely maybe to many back then, is now arriving this week - just when it is least wanted. The (usually) low AAM bias driven GEFS modelling unfortunately looks like striking accuracy with unerringly bad timing this week  (much as it did in early June to provide that highly underwhelming first half of summer)  

The upside possibilities were based on both an ocean/+AAM atmospheric circulation and tropospheric/upper +WQO driven stratosphere disconnect being sustained much longer than has proved the case.

Conclusion: It is not the "background signals" that have failed. It is simply that downside potential based on the different paths those signals might take, that has come to being, and it is the expectations of (some) of the audience, who have focussed on the upside possibilities at the expense of the less appealing option that showed what could go wrong, who are left disappointed and believing that those signals are wrong/pointless instead.

Nick S butterfly effect also is highly relevant here - especially when looking at signals almost a month ahead. In the case of the GSDM (essentially a model system that combines tropical and extra tropical forcing signals to provide "ahead of time" forecasting assistance to gauge jet stream and global weather patterns) it requires a non-bias approach to the findings in order to fully utilise the full worth of this "weather tool"

Otherwise, skewed interpretation leads (most obviously) to inaccurate results and a lack of growth in progressive knowledge and undestanding 

So the reason for my continued repetition is simply for genuinely well meant reasons to want to give the truth, and certainly not to try to appear holier in any way It shouldn't really need stating, but I can say that my own preferences are highly in tune with the majority. I'm disappointed as well, and would readily agree it not always easy to stay wholly objective when there are compelling NWP signals that appear to support upside long range underlying signals.

Having worn the t-shirt for quite a few years though, (and hopefully learning a few things on the way as well), it seems more and more wise to emphasise what can go wrong as early as that becomes apparent. This should, at least logically in theory, reduce the sense of expectations being overly short-changed. It also is another lesson that both long range NWP ensembles and also long range model stratospheric forecasts should be treated with caution - as tempting as it is to want to embrace the good things they might suggest at a given time.

Yet another year, but essentially, its the same lesson. Human preference and emotion are not equal to the science that drives the weather patterns - irrespective of what one may hope for

With that said, TEITS has a very good point about instinct. Human intervention, interpretation, and drawing on past experiences is important in deciphering and making much more user friendly, the robotics of model calculations and conclusions. It also adds much needed personality into what can otherwise appear a soulless, over geeky straight-jacket. I doubt many would post on here if it was an exclusive robot club 

A bit of further extra reality is needed though. There are far worse things happening in the outside world of the net weather bubble, and - more positively as mcweather rightly suggested this morning, there are families and friends to focus on with Christmas approaching. However appalling the weather looks set to be.

We all know that the UK lies at a massive traffic light junction with a massive ocean one side and very large continental landmass the other. Unfortunately the colder (in winter) landmass lies downstream from us, and our prevailing weather, usually, comes from upstream. All the more reason why ocean/atmospheric signals that engage the Pacific and determine the patterns there, are fundamental to our "fate" in terms of weather patterns.

That, in conjunction of course with the function of the winter-time stratospheric vortex. After all, the coriollis effect of the earth spinning from west to east can only be exacerbated by a westerly spinning top (as augmented by a westerly phase of the QBO)

It remains true that the faster they spin, the faster they can fall. But this isn't a time to try to attempt to turn to any future "jam tomorrow". A good time to take a break and prepare for the festive season

So, a happy Christmas to all and here is to much better things in the New Year

 

 A great post Tamara. Your posts have always pointed out that despite the various LRF,s (including the Meto) that there were always things that could go wrong and as a veteran of 56 winters I know that if it can go wrong it probably will. As Nick Sussex often points out in his posts we need so many things to fall into place for us to get a sustained cold shot and then even more to fall in place for widespread snow away from the usual suspects on high ground in the north. 

Living in central south Dorset within a couple of miles of the English channel I always start each winter from the stance that I probably won't see any long lasting cold or snow at all and then work forward from there. That way anything I do get is a bonus and I would advise any members living in lowland southern England to do the same.  Every so often a great cold spell comes along and occasionally some heavy snowfall but they are much  the rarities. The recent spell between 2008 to Dec 2010 provided some great winter weather for many but also I think raised the expectations of many in lowland England to a new higher level of expectancy than is justified by our natural climate.  In my own locale Dec2010 was the coldest and snowiest ever ( colder and snowier than 1890 or 1981) but I didn't kid myself that was the new norm because the vast majority of my other 56 winters weren't like that at all .

I am lucky enough to have memories  from 1963(just) and the snowy winters of the 1980's along with the greatest weather event of my life, The amazing southwest Blizzard of Feb 1978 the latter being an element that all lowland ( and especially) southern lowland snowlovers should hang onto and that is that you don't need a 63 or a 47 to have a phenomenal snow event of historic proportions . The models in the short to medium term look pretty dire but they can and most probably will change and with just a little bit of luck they will change enough to give lowland southern snowlovers a nice surprise at some point during the first few months of the new year.

 

[Model output discussion - 5th December 2016 - Into Winter we go]

2 minutes ago, Man With Beard said:

Certainly a trend on the last few ensemble runs to reduce the number of cold possibilities, as IDO / Nick rightly point out. A little early to say this trend is confirmed right out to D14, 15, 16 - but the PV seems to have no current plans to vacate. 

yes mwb models showing pretty much unanimous agreement on a mobile westerly out look through the Xmas period. Time to forget the models  and go off and enjoy the seasonal festivities for a while and come back after Xmas I think when hopefully some of the signs from Glosea and ecm46  will actually start to show themselves in reality instead just existing in a computer's  miscalculations.

[Model output discussion - 5th December 2016 - Into Winter we go]

35 minutes ago, nick sussex said:

Well the ECM is looking very unsettled and concerns here are these shortwaves running east and deepening quickly at the base of the trough. In terms of any snow chances well further north with some elevation could see something. Also if a shortwave runs east and remains quite a shallow feature rather than blowing up this could spring a surprise.

The upstream differences and uncertainties do impact the earlier timeframe, in particular these northern and southern stream jet interactions, phasing or not and amplitude will effect the T120 to T168hrs timeframe.

In terms of the big 3 the ECM has most scope for a favourable change, the GFS less so.

As you say Nick the ECM outlook is the best in terms of how one or two tweaks might spice things up a little if the colder pool over Europe is able to advect west slightly quicker that could lead to someone getting a nice surprise come the  big day.  I am reminded to a certain extent of xmas 1993 when out of a seemingly hopeless situation we actually managed to squeeze out a white xmas here in Dorset at an elevation of just 45metres above sea level.  I'll never forget walking home from a lockin at my local in the early hours of Christmas day and realising that what I could feel landing on my bald patch was not rain but snowflakes. Then waking to gently falling flakes on xmas morning with about a centimetre  on the ground. Picturesque but not travel inhibiting, just right.

incidentally that was the last time I actually saw snow falling on xmas day. Although I did have a six inch cover of previously fallen snow in Dec2010.

[Model output discussion - 5th December 2016 - Into Winter we go]

12 minutes ago, nick sussex said:

I can understand your frustration. But to be honest its a UK winter, whats new! If the cold can avoid the UK it does. At least with low heights in the Med theres some hope if the PV relents.

Quite so Nick one only has to look back at the archive charts for numerous cold spells  to see how the weather regime has done a complete turn around to cold from some very unpromising looking set ups

[Model output discussion - 5th December 2016 - Into Winter we go]

Just now, karlos1983 said:

there was a slight Ian F back track though a bit further on, saying December inclusive.

Thanks Karlos I stand corrected, although I stand by the fact that come later in December the output could look very different indeed

[Model output discussion - 5th December 2016 - Into Winter we go]

26 minutes ago, Steve Murr said:

 

I will try to do a longer post in a while however it would appear the EC seasonal model is broken. That would be along side the Glosea. 

This isnt a dig @ Matt or Ian- however how can we maintain northern blocking that we dont aready have?

How can we have a distinct -NAO for December when its been neutral since the start- the key word here being 'distinct'- suggestive of something lower than -1.5 on the scale-

well sadly theres nothing within the next 8 days that suggests that so as a minimum we will be halfway through December with no trace of any blocking that had been forecast all the from the outset of November-

Also, another reason why I must assume that is the inference that the trop vortex is running disconnected to the strat one-

It looks pretty connected to me, At the end of Nov the 10HPA 60N zonal mean forecast a steady rise from the outset through to the middle of the month & beyond & thevtrop vortex has followed- The AO which is the best measure has had a smooth increase from negative values to a current mean that is in touching distance of +2 in a couple of days, thats a hefty rise of 3 sigma in 2 weeks- it mirrors the strat perfect-

The dates are mirrored

 

Excluding the GFS ensembles which will always throw out a few peachy runs theres been nothing to indicate that there would be anything other that a 1/2 day transitory cold shots all the way to xmas...'

I will look at the zonal mean forecasts today but I fear it makes poor viewing...

S

Hi Steve

Ian F suggested this afternoon that what Matt actually mean't was Jan and Feb as in his words the EC seasonal December update doesn't actually cover December

so that actually gives us three weeks and a few days by which time the output could look very different indeed.

[Model output discussion - 5th December 2016 - Into Winter we go]

1 hour ago, Allseasons-si said:

I hope it's something like this.....goodness me,Merry Christmas and a happy new year every one

run it through

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=354&mode=0&carte=0&run=10

it could happen

God bless you Allseasons-Si

How good to see some optimism when so many others are showing model fatigue on 5th December ( yes 5th December). Really am surprised at some members here  not even a week into meteorological winter and seemingly already in mourning for winter 2016/17.  Surely we know by now that December rarely delivers deep cold  and snow for much of the UK. We were spoilt 2008 through 2010. The GloSea  signal for blocking has always been for the 2nd half of Dec at the very earliest. So what if it turns out to be a week or two late surely better to get some real wintry conditions in the heart of winter and so what if it is 13 or 14c next week. As another post has pointed out it was 14c a couple of days before the snowiest winter of the 20th century for gods sake. A mild week in December means absolutely sod all in how the rest of the winter will turn out.

Honestly this place beggars belief sometimes.

 

[Model Output Discussions 12z 30/11/16]

Whilst some posters set about slitting their wrists at tonights output ...........................................Its amazing sometimes when you look at old weather charts and you find  a day with a great big chunk of the vortex over western Greenland and a low pressure at 965 over southern Greenland with south westerlies blowing across across the UK along with a big azores high ridging up by Iberia and to your surprise you find its not December19th 2014 but December 19th 1962.....................................remember guys its always darkest before the dawn.

[Model Output Discussions 06z 04/11/16]

Well yet another day that has proven that taking any single operational run  at face value is completely futile. This mornings GFS06Z was a pure cold and snow lovers dream but facts are that You really need the GFS to be show something like that from run to run for a few days at least before giving it any credence whatsoever.

[Model Output Discussions 06z 04/11/16]

yet again some interesting runs this evening.

 

I think one has to be philosophical about model viewing in November.

Much as us coldies would love some lowland snow in November especially having been spoilt as recently as 2010 with ice days thrown as well even down here in Dorset.

But if one wants the greater prize of a decent and reasonably long lasting winter then one needs  to remember that no great long lasting winter ever started in November and held all the way through to the end of Feb.  1947 didn't start until late Jan and 1962/3 didn't really get going until the final week of Dec 62, indeed a look at the charts around the 19th/20 Dec 1962 would give you no sign that the coldest winter since 1740 was in the offing.

May be its just being a veteran of 57 winters but for me especially in the south of  the UK the watchword has to be patience, unfortunately we live in an order it today and get it tomorrow society which in which patience has become a dirty word. On a personal note I would happily take what's on offer for the next two weeks and have the real stuff kick around mid December as per IF and Glacier Points professional suggestions.

Again winters starting in November or early December like 2010 or 1981 don't really hold. give me a mid to late December start for the real action any day.

GP''s post earlier today is very inciteful especially given the north hemisphere view at the end of the 12z ECM and some of the GEFS charts around the same time.

One can understand after last years record warm December that people want to get things kicked off cold and snow wise as soon as possible but our greatest winters show that patience shown at this time  of year can pay huge dividends down the line.