Model Output Discussion - Winter arrives

[Ali1977]

5 minutes ago, knocker said:

Despite some trough disruption/wave breaking towards the end of the ten day period causiung a slight wobble vis the position of the surface high

The ext mean anomalies this morning indicate little change with the NH profile

And the clusters pretty much support this view, albeit they will of course have various options

 

 

The Heights look to have moved a little north of the U.K. on the clusters, hopefully a colder HP if nothing else.

Edited December 11, 2021 by Ali1977

[Anthony Burden]

1 hour ago, Nick F said:

Morning.

A nice tease from EC at day 10, from then on you'd want heights to drop to the S of the UK under the ridge centred near Iceland to prevent the high from sinking and allow deep cold to be advected in from the NE.

The 00z GFS briefly follows a similar route but a day or 2 later, but it then implodes and shows the danger of heights not lowering over SW Europe and the ridge toppling with the deep cold over NE Europe dropping south to to the Balkans / SE Europe rather than towards us.

Still plenty for coldies to be optimistic about, most models currently agree that the ridge extends NW towards Iceland from around the 19th - but crucially we just need heights to lower over SW Europe, otherwise the deep cold is headed for SE Europe.

Hi Nick, if that high pressure shown by ECM 216hrs/240 hrs pushes strongly Northwest the Atlantic low pressure’s may

get diverted south .

[damianslaw]

You won't find many Decembers last 40 years or so showing the current synoptical model output lead in to Christmas. It's very rare to see sustained settled high pressure on the scene mid to late December overhead. 2006 and 2007 nearest examples..  the high collapsed south in both cases post christmss 2006 pre Christmas 2007. 

[Nick F]

Trend over the last 6 runs from the GEFS for 10 days away to subtly shift the core of the NW Europe block and H500 anomaly further north up until the most recent run.

[Nick F]

9 minutes ago, damianslaw said:

You won't find many Decembers last 40 years or so showing the current synoptical model output lead in to Christmas. It's very rare to see sustained settled high pressure on the scene mid to late December overhead. 2006 and 2007 nearest examples..  the high collapsed south in both cases post christmss 2006 pre Christmas 2007. 

Dec 2005 - high built N over UK towards Iceland on Christmas Day - similarly strong TPV over Greenland, deep cold sinking south over NE Europe. That evolved into a ridge building N of the UK and into Norway allowing a brief but cold easterly after Xmas, brought some snow to parts of the east and SE. 

25 Dec 2005

27 Dec 2005

[Methuselah]

I confess. I'm already getting bored with high pressure. So, I've decided to resort to my childhood obsession with what might happen out east:

    

The colder the source-regions, the better the long-term prospects?

Edited December 11, 2021 by Ed Stone

[matty40s]

On 11/12/2021 at 08:10, sheikhy said:

I mean gfs ensembles showing me temps of 10 degrrees and 5 by night for the next 10 days!that is frikkin balmy to me!how is that even possible under a high directly over us at this time of the year!!surely there shall be some crazy inversions?!!anyone got the temps from ecm?!i was thinking sub zero at night at the very least especially with no cloud!!

Met shows not a single sunshine ray between now and next Saturday

 

[Purga]

7 minutes ago, matty40s said:

Met shows not a single sunshine ray between now and next Saturday

 

At least it will be mild

[tight isobar]

On 11/12/2021 at 09:09, Nick F said:

Dec 2005 - high built N over UK towards Iceland on Christmas Day - similarly strong TPV over Greenland, deep cold sinking south over NE Europe. That evolved into a ridge building N of the UK and into Norway allowing a brief but cold easterly after Xmas, brought some snow to parts of the east and SE. 

25 Dec 2005

27 Dec 2005

Remember that well- Although the encouragement this time is the Pacific side shenanigans .A defined cut into the pole while we have our very own becoming accomplished Synoptics- this side of the water!. Ya gotta say it’s preety promising looking

[sheikhy]

11 minutes ago, matty40s said:

Met shows not a single sunshine ray between now and next Saturday

 

And i guess that could be the issue here!a front probably gets trapped inside the high!if thats the case we better off just having the crappy wind and rain!!im not even gona bother with what the models are showing at 192 hours!!been bit far too many times over the years to take all that seriously!!gona wait till it gets to around 120 hours before i even contemplate thinking bout snow!!!i see nothing exciting at the moment!!yes a few eyebrow raisers around the christmas period but thats about it!!!

[Climate Man]

17 minutes ago, Ed Stone said:

I confess. I'm already getting bored with high pressure. So, I've decided to resort to my childhood obsession with what might happen out east:

    

The colder the source-region, the better the prospects?

Nothing wrong with high pressure.  Builds a local cold pool and chills the ground and sea. The important bit is which way it eventually moves.  As you say, hopefully it opens the door to the East. 

[damianslaw]

28 minutes ago, Nick F said:

Dec 2005 - high built N over UK towards Iceland on Christmas Day - similarly strong TPV over Greenland, deep cold sinking south over NE Europe. That evolved into a ridge building N of the UK and into Norway allowing a brief but cold easterly after Xmas, brought some snow to parts of the east and SE. 

25 Dec 2005

27 Dec 2005

Oh yes I was commenting on pre Christmas high pressure on the scene from 17th and past Christmas.. 

[Anthony Burden]

30 minutes ago, Nick F said:

Dec 2005 - high built N over UK towards Iceland on Christmas Day - similarly strong TPV over Greenland, deep cold sinking south over NE Europe. That evolved into a ridge building N of the UK and into Norway allowing a brief but cold easterly after Xmas, brought some snow to parts of the east and SE. 

25 Dec 2005

27 Dec 2005

Hi Nick,quality information regarding Northern blocking can you say if both years when that happened was there

an EQBO /La-Nina/MJO-6-7

[Singularity]

Notable sharpening trend to the Eurasian ridge-trough leading to increased cold air transport down to our east and raised chances of that heading west around the southern flank of the high, in turn raising odds of LP development to the south or southeast, which sets up a cut-off high (best for easterly in south) or omega block (could be cold but probably very dry).

I recall a similar adjustment in the run-up to the late Nov 2010 spell. Not comparing for magnitude of outcome, just noting that even then, when so much was aligned for a big cold spell, the models initially underestimated the cold air plunge and cut-back on the eastern flank of the blocking high pressure.

[Lukesluckybunch]

lets see if on the 6z we can pump the high even further into greenland.perhaps covering the whole of it not just the southern tip.big ask i admit.

[PiscesStar]

27 minutes ago, Lukesluckybunch said:

lets see if on the 6z we can pump the high even further into greenland.perhaps covering the whole of it not just the southern tip.big ask i admit.

Why?? Youre a lucky guy!! 

[Lukesluckybunch]

1 minute ago, PiscesStar said:

Why?? Youre a lucky guy!! 

haha most the time

[Methuselah]

Oh dear, my latest thinking (hoping!) is that, following a brief spell of quasi-zonality (sometime around New Year) much colder air will spread south. Meanwhile, and depending on cloud-cover, a longish spell of late December grot might ensue:

    

[tight isobar]

Lol- 6z blanks Greenland - and goes all Scandinavian- the probably route in fairness..

[Battleground Snow]

3 minutes ago, tight isobar said:

Lol- 6z blanks Greenland - and goes all Scandinavian- the probably route in fairness..

I think it's still coming, just a slower evolution

[Lukesluckybunch]

3 minutes ago, tight isobar said:

Lol- 6z blanks Greenland - and goes all Scandinavian- the probably route in fairness..

better run in my opinion even a easterly flow for a time.eventually its heading to greenland at 192

[tight isobar]

On 11/12/2021 at 10:25, Battleground Snow said:

I think it's still coming, just a slower evolution

Yeah- certainly, although as keeps being mentioned plenty of meat on the bones of this yet. The possitive bit though- is it’s not far from certain now that the cell goes north- of some direction @ and that’s all gravy.

[I remember Atlantic 252]

7 minutes ago, tight isobar said:

Lol- 6z blanks Greenland - and goes all Scandinavian- the probably route in fairness..

Want this in May to late August! very rare then though

[sheikhy]

7 minutes ago, I remember Atlantic 252 said:

Want this in May to late August! very rare then though

Without falling for what the gfs keeps churning out every run all im seeing mate is high pressure over the uk and nothing else!!if that means a cold and frosty high i will take it!!my worry is again without paying attention to these ridiculous charts close to fi is that we gona have the high over the uk for such a long period of time for it to then just sink slowly but surely and we are back to westerlies!before you know it we in the 2nd week of january and half of winter has gone together with the longest nights!!but the cycle will continue and my fellow coldies shall keep looking into fi!!

[frosty ground]

On 11/12/2021 at 10:43, sheikhy said:

Without falling for what the gfs keeps churning out every run all im seeing mate is high pressure over the uk and nothing else!!if that means a cold and frosty high i will take it!!my worry is again without paying attention to these ridiculous charts close to fi is that we gona have the high over the uk for such a long period of time for it to then just sink slowly but surely and we are back to westerlies!before you know it we in the 2nd week of january and half of winter has gone together with the longest nights!!but the cycle will continue and my fellow coldies shall keep looking into fi!!

I do miss the laughter emoji