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

[Cheshire Freeze]

Well the GEFS at extended range are perhaps one of, if not the, most promising suites I've seen thus far. Heights getting to an increasingly northern latitude is a common theme- along with the much touted retrogressive heights

Bang on cue too...i.e Christmas- New Year week

Edited December 14, 2016 by CreweCold

[nick sussex]

6 minutes ago, fergieweather said:

:-) 'phone Adam Scaife and his team before they meet on Monday, Nick... as that's the very enigma they're trying to resolve even before discussing the next 3 months!

The fact remains that trying to fathom where these longer range outputs lead us *is* creditable: after all, they underpin everything we later see modelled at shorter range. And just as we see UKV misrepresent (or even miss altogether) the behaviour of a shortwave trough even at T+6hrs, we'll sure as dammit see times when a seasonal coupled model messes-up at T+600 hrs. It'll happen. We accept it. We run hindcasts; we learn; the model learns. Science advances. Snippet by snippet...

Whilst it's very easy to trash the seasonal or 30d models (primarily by people seemingly obsessed with some sole desire of snow, or who wrongly assume blocking=frigid), it's intriguing that many of those who devalue the long range bespoke models then willingly accept deterministic output so faithfully at those extended ranges as 'proof' of the extended lead models being 'wrong".

That's a judgement we can reasonably make at around 5-7 days. But not at 10-15.

I seem to have opened up a can of worms this evening! lol I'm not disputing that there have been advances in the modelling but I think theres only so far this can go. The problem is in a laboratory its far easier to isolate out variables whereas in the atmosphere its far more complicated. I don't believe science will ever be able to accurately forecast months ahead. Indeed one only has to look at the disaster NCEP have just had with their initial December forecast to show how difficult even forecasting a month ahead can be. That's not to say that science should give up on this but that as I said earlier in the thread its trying to solve a puzzle that can't be solved.

[Cheshire Freeze]

vs climatology at that range, this is one impressive ensemble mean...384 hrs

One even gets the impression that the vortex could blow itself apart some time in January given its (very) quick departure from a slumber throughout November...as some have indeed hinted in the strat thread. This is something which wasn't looking likely initially i.e with the continued depressed vortex forecast for December. Hence a slow decline into mobility was initially more favoured once the sluggish vortex phase ended. It's no wonder the modelling and pros alike are having a torrid time thus far.

The odds of a more sustained severe spell of winter weather sometime during the core of winter have shortened IMO.

Edited December 15, 2016 by CreweCold

[Guest]

@Tamara - You were absolutely right to make your comments. I can clearly see how exasperated you felt. Reading some of the posts today, I was considering making some similar points myself, which I will now.

This evening, things have got completely out of hand - far worse than just the usual one liner moans. There have been a few excellent posts but these get swamped by the utter dribble expressed by some other posters which makes it a very hard slog for anyone trying to catch up with the latest on this thread. Yes, everyone should think before they make their comments. Genuine, reasoned and constructive criticism put across politely is fine. We are all very fortunate that the professionals and more experienced amateurs are prepared to give up their time to make some excellent contributions to this thread. Please treat them with respect. We all need to make an effort to ensure that this model thread is a pleasant environment for everyone. Although there have been some comments and warnings from several moderators, far too often these are ignored. 

As far as I'm concerned, the huge unpredictability of this Winter is absolutely fascinating. Let us all enjoy the ride but in a civilised way. I'll be back with my next weekly report in 4 or 5 days time.

Edit - Additional Comment:

@nicksussex  - I do not think that Tamara was aiming her comments solely at you. It was more an accumulation of criticism from a number of posters with some ill judged and quite unfair remarks. You are a highly respected regular contributor. It can be difficult to apologise but I am sure that your last post this evening (on page 121) which is well put, will clear up any ill feeling. I just hope that others can show the same respect. 

Edited December 15, 2016 by Guest
Additional comment

[feb1991blizzard]

19 minutes ago, Steve Murr said:

Its worth putting on the pad for review tomorrow

You never get true 850 depth from easterly ENS data until sub 96 hours- even at 48 ive seen -10/s becomes -13s ( mar 13 IIRC )

Look at 150 on

PTB 1,2,3!!!,6,7,8!!!,11 !!,14,15!!,17-

There are some decent ens yes.

[Nouska]

4 minutes ago, sawan said:

Guys I am really struggling to follow here . I value all the senior (more knowledgeable) members , no criticism on anyone, I have read a few pages from earlier today and guess what I am confused now . Who should be followed? Got no clue. On top of that we have already started a blame game. Please keep posting and sharing and also consider the junior (less knowledgeable) members like myself and many more on here . Thanks.

you have lots of company in the confused corner - including the Met Office boffins!

The only blame to be apportioned should be on not looking across a wider spectrum of model output - a lot did not concur with the idea of a blocked pattern conducive to the cold and snow so many desire. This is maybe the fault of some not understanding the climatology the anomalies are set against or just assuming northern blocking to the north west was an automatic cold signal.

We'll no doubt, in time, have a forensic assessment of where things went wrong for this month but failure is part of the advancement process and maybe lead to better forecasts somewhere in the future. Nick and Tamara are both right in their critique - too many butterflies fluttering all over the globe but Tamara does do a great job as our resident lepidopterist.

 

 

[feb1991blizzard]

20 minutes ago, CreweCold said:

CFS Jan anomalies just where we want 'em

Yes, although the temps the temps don't match up - this is a question to Ian more than anything, why do temps never seem to match the blocking levels on long range models?, surely this is something that would be relatively easy to tweak?

[SMU]

The only real assessment that really needs to be made by METO is why that 'strat top' models missed the boat on the 40M/S swing in the 10HPA 60N zonal mean from 10M/S on Nov 25th & again @ 13 M/S on Dec 3rd to where we are now 10 days later @ near 50M/S - 

If the models cant model the variability in the strat then they cant progress forward.

ECM shows continued clear downward propergation

PS I will add this daily

CFS DATE FOR SSW IS 14th Jan ..

 

 

Edited December 15, 2016 by Steve Murr

[Snowman.]

Who needs a polar vortex? 

 

Edited December 15, 2016 by SN0WM4N

[snowray]

New trend spotted there from around the 20th, could the old BOM be the trend setter after all I wonder?

Big turn around from the ECM tomorrow?

[SMU]

Hot off the press

18z NAVGEM 144-

The 2 main player storyline has now officially been upgraded to 3 main players

* atlantic energy

* Scandi heights

* Iberian - Italy troughing

[Cheshire Freeze]

5 minutes ago, Steve Murr said:

Hot off the press

18z NAVGEM 144-

The 2 main player storyline has now officially been upgraded to 3 main players

* atlantic energy

* Scandi heights

* Iberian - Italy troughing

Even if this opportunity is a bust, I think the E'ly will come sooner rather than later, Steve. Saw a post elsewhere that said the pattern thus far has been reminiscent of that you'd see in a drought summer and in drought summers you often see an E'ly manifest at some point.

Have you seen the extended range GEFS mean?

Edited December 15, 2016 by CreweCold

[SMU]

14 minutes ago, CreweCold said:

Even if this opportunity is a bust, I think the E'ly will come sooner rather than later, Steve. Saw a post elsewhere that said the pattern thus far has been reminiscent of that you'd see in a drought summer and in drought summers you often see an E'ly manifest at some point.

Lets hope so-

Its the very best we do from a dire NH profile- we are just lucky that the vortex is displaced around 1000 miles to the NW keeping the storms away & allowing that finger of high pressure over scandi because the overall heights are pretty inline with 2015-

Anyway, theres a BIG signal late this eve from some minnows- enough to herald my extra interest early doors tomorrow-

The NAVGEM has battleground written all over it!

S

Edited December 15, 2016 by Steve Murr

[Daniel*]

57 minutes ago, MR EXTREMES said:

But this is not supported by any other model.

But at that time frame it would have been interesting if it was supported.

As with all things, you need to start somewhere perhaps tonight is the night.

I'm a fair bit more encouraged some good ens members not limited in number, showing a more resilient block with a cold pool in the vicinity of the UK - lets see what today brings...

Edited December 15, 2016 by Changing Skies

[nick sussex]

As I seem to have started this LRF drama this evening perhaps its time to move on. We all have our differing views about the worthiness of these. At the end of the day the majority of the members in here would love to see some snow, we're basically all rooting for the same thing. Certainly this thread should be one place where things shouldn't get personal or seem to be that way.

This is a strange place, in a weird sort of way its our little comfort bubble. Its a  place where the search for snow turns into a melodrama with obvious ups and downs, where occasionally we throw our toys out of the pram and where it can become emotional. With that in mind I'd like to firstly apologize to Tamara because my post could have been better worded, we should never forget that snow lovers share a special bond. A lot of people really think its a bit weird or are too frightened to say that snow makes them happy or makes them feel in a way disconnected from the real world or similarly that the world just seems better when its snowed!

This post may come across as alcohol driven and yes it is, but we often say what we mean when we lose some of those inhibitions that soberness brings! lol It might come across as rather mushy especially for someone close to hitting 50, yuk! I may regret this outpouring of honesty in the morning, thoughts of what was I thinking or will members think I've lost the plot, that may not be far from the truth!

Anyway that's what I had to say and I've said it. I will be back to my less melodramatic self in the morning where hopefully we can see tonights more positive GFS 18hrs trend continue!

[Weathizard]

2 minutes ago, Steve Murr said:

Lets hope so-

Its the very best we do from a dire NH profile- we are just lucky that the vortex is displaced around 1000 miles to the NW keeping the storms away & allowing that finger of high pressure over scandi because the overall heights are pretty inline with 2015-

Anyway, theres a BIG signal late this eve from some minnows- enough to herald my extra interest early doors tomorrow-

The NAVGEM has battleground written all over it!

S

When you're reaching for the NAVGEM you know things are desperate! It's a cannon fodder model to be frank. That being said, let's hope it is a trendsetter.

[feb1991blizzard]

Still no London EPS Ensembles at 1230, strange.

[Duane S.]

58 minutes ago, fergieweather said:

:-) 'phone Adam Scaife and his team before they meet on Monday, Nick... as that's the very enigma they're trying to resolve even before discussing the next 3 months!

The fact remains that trying to fathom where these longer range outputs lead us *is* creditable: after all, they underpin everything we later see modelled at shorter range. And just as we see UKV misrepresent (or even miss altogether) the behaviour of a shortwave trough even at T+6hrs, we'll sure as dammit see times when a seasonal coupled model messes-up at T+600 hrs. It'll happen. We accept it. We run hindcasts; we learn; the model learns. Science advances. Snippet by snippet...

Whilst it's very easy to trash the seasonal or 30d models (primarily by people seemingly obsessed with some sole desire of snow, or who wrongly assume blocking=frigid), it's intriguing that many of those who devalue the long range bespoke models then willingly accept deterministic output so faithfully at those extended ranges as 'proof' of the extended lead models being 'wrong". 

That's a judgement we can reasonably make at around 5-7 days. But not at 10-15.

Ian, I've highlighted above the aspect that always seems to be the most commonly misinterpreted in these situations on this forum. What is often forgotten/overlooked/ignored is that we will almost always need high(er) latitude blocking to achieve a proper cold spell but high(er) latitude blocking does NOT guarantee it!

[Abyss]

2 hours ago, Tamara said:

The downsides (as well as the upsides) of the way forward for the start of winter into beyond were highlighted before the long range models started to move away from the predominant blocking signal to the NW - which had been well advertised at the end of November.  I alone have spent the last week, at least. repeating this because it was either being selectively ignored or because it hadn't yet snowed as (allegedly) had been promised). .

Which illustrates well the point that Catocol makes, that the MJO, GWO, OJO-flip blah blah are only deemed useful to some when the models (who derive their input from these signals in the first place) support the synoptics the majority hope for.

If these "global signals" are a subject of mystical folklore, unless it suits, then it will have to be forgiven the reaction that comes back from others who value them for the true purpose they provide in terms of giving a heads-up where NWP may evolve in the future. Its not the messengers fault if they don't eventually promote raging blizzards.

I neither profess myself in the slightest to be any special expert, soothsayer or have some clever inner perception that none else possesses, but what is frustrating is to keep seeing these misrepresented perceptions endlessly peddled - especially when you know that a balanced analysis has been attempted..which says as much about what can go wrong (according to the uncertainty of the "global signals") as can go right.

Speaking personally I've had to resort to even signposting where a post was deliberately taking a upbeat stance and the cautious "what might go wrong" stance. That should never be necessary - people should be able to read between the lines themselves before pulling the trigger.

In that sense I am most fed up of the constant misrepresentations and the obvious fact that the posts haven't even been read properly in the first place before response made. They are meant to be  taken as on-going summaries which are meant to illustrate transparency in the first place. If the intent was to somehow try to be clever and or just soley want to tell everyone what they want to hear, why bother to invest time and energy into setting out the posts this way in the first place?. Its as much about seeing what doesn't go according to plan, as it is about seeing what evolves according to expectations. If trying to be the pied-piper was the intention, then I think there would be better reason to be hung out to dry.

Its because the GSDM (incorporating both tropical and extra tropical signals that have a massive effect on global weather and jet stream pattern) can help give a starting insight to NWP that matters. Its not about the type of tiresome neanderthral LRF competitive one-upmanship that permeates this thread every winter.

Speaking personally I don't even do LRF'S

Its also unfortunately the same (relative minority) of armchair critics that turn out as part of this tedious, unconstructive and divisive process - when expectations and hopes are not met.

 

People are entitled to their view that LRF are hocus pocus.... . If Jesus Christ himself gave his Winter prediction I would take it with a pinch of salt. People need to stop being so sensitive. This Winter was a massive fail in terms of LRF from the Met Office concerning front loaded cold. That is a FACT. Yes things constantly change as you've alluded to and that is exactly the point, things change in the short term that rubbish predictions for the long term. No one is being attacked, I don't buy LRF or give much credence to these background signals as they usually amount to nothing. I respect that other people do, and they should respect those who don't. To be accused of being an armchair critic for simply having a different viewpoint is childish. Difference of opinion is a wonderful thing. 

[Penrith Snow]

3 hours ago, nick sussex said:

As I seem to have started this LRF drama this evening perhaps its time to move on. We all have our differing views about the worthiness of these. At the end of the day the majority of the members in here would love to see some snow, we're basically all rooting for the same thing. Certainly this thread should be one place where things shouldn't get personal or seem to be that way.

This is a strange place, in a weird sort of way its our little comfort bubble. Its a  place where the search for snow turns into a melodrama with obvious ups and downs, where occasionally we throw our toys out of the pram and where it can become emotional. With that in mind I'd like to firstly apologize to Tamara because my post could have been better worded, we should never forget that snow lovers share a special bond. A lot of people really think its a bit weird or are too frightened to say that snow makes them happy or makes them feel in a way disconnected from the real world or similarly that the world just seems better when its snowed!

This post may come across as alcohol driven and yes it is, but we often say what we mean when we lose some of those inhibitions that soberness brings! lol It might come across as rather mushy especially for someone close to hitting 50, yuk! I may regret this outpouring of honesty in the morning, thoughts of what was I thinking or will members think I've lost the plot, that may not be far from the truth!

Anyway that's what I had to say and I've said it. I will be back to my less melodramatic self in the morning where hopefully we can see tonights more positive GFS 18hrs trend continue!

Up all night as I have a crises in my life but this post has really cheered me up.

Yes, the desire for snow is irrational but it has shaped the lives of most of us on here, it's harmless, it's fun and I always think of other posters on here as 'friends'.

Cheers everyone and have one for me Nick!

Andy

[northwestsnow]

Hard not use emotive language when describing that UKMO run this morning,suffice to say its not good for those of a cold persuasion,the jet barreling through scandy and beyond.

GFS slightly more amplified but even right through to the end of the run that vile PV still sat across Greenland..

384hrs

Prior to that quite a lot of rain over the festive period.

In fact,running through the precip charts,its horrendous.

Don't think there is going to be much joy in here today..

Edited December 15, 2016 by northwestsnow

[IDO]

Looking at the GFS op this morning:

We have the HP system to our east throughout the 16 day run.

The attack from the vortex from D5 sends the LP systems coming from NW/W to the NE so the LP systems do not cross the UK; glancing blow.

Rain therefore from fronts and the SE favoured in these set ups (for less rain).

3 fronts forecast at the moment, from D6 to D10; then far NW main risk rain.

HP then builds back in (uncertainty re specifics).

Counted no frosts for the rest of December in England (and probably Scotland) with uppers consistently above seasonal average.

Again no sign of anything remotely interesting for snow or cold, though D7-9 some PM air maybe giving some cold rain to seal-level in the North/NW. 

London 2m temps next 7 days; mild to average:

So the interest remains how HP develops from D11?

[northwestsnow]

1 hour ago, Penrith Snow said:

Up all night as I have a crises in my life but this post has really cheered me up.

Yes, the desire for snow is irrational but it has shaped the lives of most of us on here, it's harmless, it's fun and I always think of other posters on here as 'friends'.

Cheers everyone and have one for me Nick!

Andy

Sorry you got problems Andy, I used to post on TWO myself so am acquainted with you.Hope things sort themselves out for you..

Both ukmo and gfs offer little festive cheer, I'm hoping ecm might offer something better.

Edited December 15, 2016 by northwestsnow

[knocker]

Today

Not a great deal to say about the weather at the moment. Most of Britain will remain cloudy with some patchy sunshine in places and maybe sporadic drizzle. Some rain in N. Ireland and NW Scotland later as another front stalls and deconstructs just to the west. Temps remaining on the mild side except the far north of Scotland

There would appear to be some adjustment to the upstream pattern this morning with the main lobes of the vortex over the Arctic and, more importantly, quite intense over the tip of Greenland. This pushes the Atlantic trough a little further west and south whilst simultaneously edging the HP further east thus probably removing any influence from it over the Xmas period. After day ten yet more pattern changes with the GFS continuing in retrogression mode with positive anomalies again to the NE with a weak trough on the western horizon. More on this no doubt later.so back to the here and now.

After getting the weak front out of the way pressure will once again surge over the weekend and just about stays in charge until the middle of next week. Worth keeping an eye on the cut off upper low over Iberia which becomes quite active.

The next attack from the large, complex, upper trough succeeds in disrupting the ridge, phasing with the Iberian low and pushing the HP cell east.

This marks the beginning of a very wet and windy few days as the upper trough boots up systems that swing into the UK with the Xmas period not looking too clever if this scenario is anywhere near correct.

Not much more to be said. remaining dry until the middle of next week and then as already stated. Temps around average, As I write salutations to the retrogression are echoing around the chamber.

 

Edited December 15, 2016 by knocker

[ArHu3]

 

And then ecwmf comes with this surprise and only +144h out