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

[Singularity]

26 minutes ago, nick sussex said:

Its hard to see where that amplification is going to come from , the MJO isn't really moving anywhere fast. Last week there were issues with conflicting signals. The latest NCEP update will be tomorrow.

There's a bit of activity at >1 amplitude in phase 3 expected later this week, which helps to build a mid-latitude block in our vicinity (but likely centred a little east of UK).

However the ECM 12z seems to have decided to do away with this signal and, judging by how easily it slices a shortwave through Iceland early next week, the lower-stratospheric forcing as well. I honestly went into a minor state of shock when scrolling through it for the first time - and that's with my experience telling me not to take individual det. runs seriously beyond 5 days range! To take a huge dump all over the recent model trends like that is diabolical.

I don't know if GP was suggesting this sort of thing when he talked about how it would be interesting to see what the eastward shift in analysed tropical forcing would lead to 

[SLEETY]

1 hour ago, Summer Sun said:

The start of Christmas week still looks colder

That's better,the minus 10 line is being breached again,we want to see these increase in the coming days 

Thet 

The posts here are depressing have the met seasonal models really got it so so wrong 

[Frosty.]

9 minutes ago, Frosty. said:

I hate the term Euro slug, isn't there a better name for it..like Eurotrash High or Bartlett

Anyway, it's what the models are showing which is the name of the game after all!

 

There is no gain without pain folks, we will have to ride this out and hope for better ( colder ) later in the month..which is still what the GEFS mean is indicating with increasing high pressure and a probable return of surface cold from around mid month onwards.

Edited December 5, 2016 by Frosty.

[blizzard81]

4 minutes ago, Singularity said:

There's a bit of activity at >1 amplitude in phase 3 expected later this week, which helps to build a mid-latitude block in our vicinity (but likely centred a little east of UK).

However the ECM 12z seems to have decided to do away with this signal and, judging by how easily it slices a shortwave through Iceland early next week, the lower-stratospheric forcing as well. I honestly went into a minor state of shock when scrolling through it for the first time - and that's with my experience telling me not to take individual det. runs seriously beyond 5 days range! To take a huge dump all over the recent model trends like that is diabolical.

I don't know if GP was suggesting this sort of thing when he talked about how it would be interesting to see what the eastward shift in analysed tropical forcing would lead to 

I understood GP to mean quite the opposite - more amplified and interesting runs but I may have totally misunderstood?

[NorthernRab]

I really can't understand the pessimism in here. Folk need to stop looking at every single deterministic operational run and keep an eye on the ensembles. They're all pointing towards a marked cool down towards mid month after the upcoming (and very brief by UK standards!) mild spell which starts tomorrow. 

 

The below chart sums things up nicely in this regard. 

 

Half full and all that.

[blizzard81]

3 minutes ago, NorthernRab said:

I really can't understand the pessimism in here. Folk need to stop looking at every single deterministic operational run and keep an eye on the ensembles. They're all pointing towards a marked cool down towards mid month after the upcoming (and very brief by UK standards!) mild spell which starts tomorrow. 

 

The below chart sums things up nicely in this regard. 

 

Half full and all that.

I think the reason people on here are worried is because op after op after op shows didly squat in terms of real cold. When the ops are run at a higher resolution, I can personally understand all the pessimism. 

Edited December 5, 2016 by blizzard81

[SMU]

^^^ to be fair why are you using the Highland T2Ms to represent the Uk..

 

[Frosty.]

4 minutes ago, blizzard81 said:

I think the reason people on here are worried is because op after op after op shows didly squat in terms of real cold. When the ops are run at a higher resolution, I can personally understand all the pessimism. 

But the Gefs mean shows a return of cold surface conditions with  high pressure from mid month which is only 10 days away.

Edited December 5, 2016 by Frosty.

[blizzard81]

It is also concerning that the glosea model is now less bullish about blocking when compared to last week. Fergie confirmed this earlier.

[I remember Atlantic 252]

6 minutes ago, NorthernRab said:

I really can't understand the pessimism in here. Folk need to stop looking at every single deterministic operational run and keep an eye on the ensembles. They're all pointing towards a marked cool down towards mid month after the upcoming (and very brief by UK standards!) mild spell which starts tomorrow. 

 

The below chart sums things up nicely in this regard. 

 

Half full and all that.

not many of us live there though! good ens for you, but not for south

[Paul White.]

7 minutes ago, Frosty. said:

I hate the term Euro slug, isn't there a better name for it..like Eurotrash High or Bartlett

Anyway, it's what the models are showing which is the name of the game after all!

 

One of my favourites from a few years ago was the term "displaced bartlett" lol

 

 

[Man With Beard]

Over the weekend I was 50/50 over blocking or vortex ... I'm afraid I'm down to 30/70 today, simply because I would expect at least some backing from the ops by now. You have to favour the ops when they are so consistently for a certain solution. Looking more unlikely, then, to see cold during the middle part of December, imo. 

Hey, there always the final third of December!!

[karlos1983]

2 minutes ago, blizzard81 said:

I think the reason people on here are worried is because op after op after op shows didly squat in terms of real cold. When the ops are run at a higher resolution, I can personally understand all the pessimism. 

If we had the odd OP that throws a decent run in then I'd happily go along with it, but we haven't. The odd sniff of a height rise which collapses as quickly as it came due to the energy upstream. I'll keep an open mind for now, but we need to see the op at least to get sort of inline 

[blizzard81]

1 minute ago, Frosty. said:

But the Gefs mean shows a return of cold surface high conditions from mid month which is only 10 days away.

Whilst this is welcome, these ensembles can and do easily flip at that range. This tends to happen more often when the op runs stay resolutely against cold. I am feeling like you did on Saturday lol

[damianslaw]

As ever best sticking to reliable timeframe i.e. 144 hrs. I said yesterday for those who don't like seeing zonal westerly flow being shown on the charts beyond such timeframe, best wait until Thursday, as I fully expected today's kind of charts to be thrown up by the models until then.

My hunch is we will see the azores high/ euro ridge build northwards into the country from mid month onwards, with the atlantic trough amplifying somewhat - warm air advection aloft, and and consequently will end up with a split jetflow, but perhaps more energy going into the northern arm, thus preventing any heights building sufficiently to our north, but every chance they will build NE, to pull in a colder continental flow as we approach christmas.

Back to the reliable, after weeks free of the dreaded southwesterly it once again rears its head.. just have to ride it out for a bit. Its not like we haven't been here before on far too many occasions in early December to remember..

[Captain Shortwave]

The GFS ens do show surface temperatures in the south dropping a little below normal (5/6C) so there is a cool down and no clear signal moving forward. That said anyone getting excited by the control run, it shows a large Euro/Scandi ridge with a south/south easterly flow so a cold surface set up with sunny days and frosty nights.

      

Looking at the ensemble anomalies

      

Look solid with building another mid-latitude high close or just east of the UK actually as per the control run and the GFS parallel. I can't see any blocking setting up to our north west as the Pacific profile is set up poorly as cold Siberian air is allowed to drain towards Canada by that Aleutian high. That said I remain unconvinced of the full zonal signal given the tropospheric vortex isn't that strong so maybe a drier and cooler picture after mid-month, though snowy conditions will require a bit of luck in my view.

Oddly this signal has been solid from the GEFs and CFS monthly guidance for after mid-month and sits well with the metoffice mid-range forecasts too.

Edited December 5, 2016 by Captain Shortwave

[Stuie]

Haven`t posted for a while but been watching with real interest due to a completely chillier start to winter in relation to previous years. I have to say this forum has been hard to read tbh, almost bi-polar at times with some posts.

I don`t have a lot to add with the current output which does appear to trend milder then back to some pretty colder days on the run up to Christmas. Blocking which has been touted is hard to see at the minute but been looking at the jet stream in FI and it does want to meander either over the UK or over but it does take a huge meander north at the end of the run suggesting that blocking HP is likely to setup somewhere around the UK. If it isn`t going to snow Xmas week then I`d like a dry one.

[bobbydog]

4 minutes ago, blizzard81 said:

It is also concerning that the glosea model is now less bullish about blocking when compared to last week. Fergie confirmed this earlier.

He said "continued but somewhat less bullish" about blocking. He also said that the GFS parallel reflected what Glosea was showing, i.e. this-

Let's not forget the important bits eh?

I'm off to the parallel universe....

[SMU]

So if you ever wanted a last depressing post & a totally different way of illustrating the possibility of snow here is the T2Ms for london in grid form for all the ensembles

from 20 runs - it takes all the way to timepoint 234 hours to see 1 run see a negative dewpoint of -0.3, & prior to 300 hours there are only 8 in incidence of a dewpoint lower than -1 ( from a choice of 20 runs x 21 timepoints )

so the very best would be 420 timepoints below -1, we have just 8 & (0 pre 228)

thats about 2% chance then...

look at the swathe of warmth through 7 days !

 

 

[Stuie]

Come on Steve, the mild spell whether 7 days or not is hardly a secret.

[SMU]

16 minutes ago, Stuie W said:

Come on Steve, the mild spell whether 7 days or not is hardly a secret.

I dont think anyone said it was?

The point I was making was related to snow & the forecast T2Ms-- which on the whole in terms of mild go way past day 7 to about day 12/13-

Luckily plenty of time for change before that lands -

 

Edited December 5, 2016 by Steve Murr

[Singularity]

J. Cohen has in some of his recent blog posts pointed out that the models have a known bias toward blocking off positive height anomalies trying to propagate down from the stratosphere when actually they should make it through and influence the 500 mb pattern. This can explain the oversights by GFS, provided one assumes the parallel has been adjusted to reduce or even remove the aforementioned bias, but the wild swing by ECM this evening remains a conundrum. Weirdly, I can recall a few occasions past where ECM has unleashed a fury of hyper-mobile deterministic runs out of the blue and then, within a day or two, stowed them away again as suddenly as they appeared. Perhaps, at times when intense thermal gradients are occurring upstream of the UK, the higher resolution causes more in the way of a feedback effect from assumed overly-efficient baroclinic processes.

This is a suspicion I've harboured for some time now, but I've not attained enough evidence to state it as fact - and still haven't, I'm afraid! I've only bothered posting it in case we do end up with a far-less mobile outcome for next week, which would be quite revealing.

Regardless of the fallibility of the op runs, it's high time we had a decent one to look at and make us smile. All we can do is wait, hope, and try not to let the lack of quick gratification get to us 

[stewfox]

5 minutes ago, Steve Murr said:

So if you ever wanted a last depressing post & a totally different way of illustrating the possibility of snow here is the T2Ms for london in grid form for all the ensembles

from 20 runs - it takes all the way to timepoint 234 hours to see 1 run see a negative dewpoint of -0.3, & prior to 300 hours there are only 8 in incidence of a dewpoint lower than -1 ( from a choice of 20 runs x 21 timepoints )

so the very best would be 420 timepoints below -1, we have just 8 & (0 pre 228)

thats about 2% chance then...

look at the swathe of warmth through 7 days !

 

 

I cant see a single 14c in there , have I missed something ?

No-one expected this winter to be severe, as January started with very mild temperatures at up to 14 °C recorded... 1947 The first snow came on 23 January, 

 

[SMU]

13 minutes ago, stewfox said:

I cant see a single 14c in there , have I missed something ?

No-one expected this winter to be severe, as January started with very mild temperatures at up to 14 °C recorded... 1947 The first snow came on 23 January, 

 

Where does 14c come into the mix?

[Dancerwithwings]

Chocolate tea pot model....http://www.meteociel.fr/modeles/cfse_cartes.php

Has this for the 10th....then for the 20th

and for the Xmas seasonal outlook lets just hope CTP Model is