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Model Output Discussion 4th Dec.2013-12z onwards.


phil nw.

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Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

Upper cold potential has been as unlikely in truth as any zonal re-set. Mid latitude high pressure has been the most likely contender for some timePosted Image

 

The evolution of the pattern as modelled has been well advertised through the last week or so of November and into this first week of December. A transfer of the polar vortex from Siberia as at the same time the Aleutian High starts to retrograde westwards into the Pacific. Essentially we see a change upstream over the coming days from a +AO/-EPO pattern to a +AO/neutral to +EPO pattern. In this way, as suggested might happen, we are at this very time in the process of losing the potential for atlantic ridging (which hasn't come to as much as some modelling flattered to deceive anyway) as the vortex energy increases to the NW and sets up a downstream ridge over nearby Europe.

 

The strength and position of the vortex ensures that any notion of heights into Scandinavia was never, imo, much of a starting consideration and with no help from the t/c's we are probably stuck with this pattern into the middle of December and beyond.

 

The positive is that the jet stream, whatever the state of the AO these post modern days, is keen to stay meridional. This stands us in good stead for the longer term, as seasonal wavelengths change, and hopefully a return of that Aleutian poleward ridge and a further re-shuffling and resumed attack on the vortex.

 

However, for the foresseable future then, a lot of patience required - at least there is little wind and rain to contend with for most parts of the UK and some continental influence should keep areas away from some NW and Western coasts with seasonally colder surface temperaturesPosted Image

 

Far to much importance is put on the Polar Vortex, your post would suggest to me that without a 'favourable' polar vortex then you can't get cold, which simply isn't true.

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Posted
  • Location: Fazendas de,Almeirim, Portugal
  • Weather Preferences: The most likely outcome. The MJO is only half the story!
  • Location: Fazendas de,Almeirim, Portugal

Far to much importance is put on the Polar Vortex, your post would suggest to me that without a 'favourable' polar vortex then you can't get cold, which simply isn't true.

The basis of my post suggests clearly that we look to have reasonable potential for surface cold from winter anticyclonic conditionsPosted Image  - but we look to wait some time yet for potential for upper cold on the basis that conditions over the polar regions for any rise in pressure, to advect cold upper air southwards, are not favourable. We also have lost, at least temporarily, the mechanism for amplification of ridging in the atlantic and associated colder incursions from that source

Edited by Tamara תָּמָר
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Posted
  • Location: Grimsby, North East Lincolnshire 16m asl
  • Location: Grimsby, North East Lincolnshire 16m asl

http://www.wetterzentrale.de/pics/MT8_London_ens.pngStraw clutching of the worst kind but at the end of the run, the op is definitely on the mild side of things and there's a few below average options...

As daft as it sounds those are the best ens I 've seen by the GFS all week. We have a dip at the end!!!!!!!!!!!!!! A positive straw to clutch.
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Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

Far to much importance is put on the Polar Vortex, your post would suggest to me that without a 'favourable' polar vortex then you can't get cold, which simply isn't true.

 

What do you think drives the NH winter synoptics?

 

At its most simple concept - the PV is the steering wheel which controls the direction of upper air flow and subsequently the weather on the ground

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Posted
  • Location: Near Keele, North Staffs
  • Location: Near Keele, North Staffs

ECM now fully out and the jet is blasting to Western Russia, if this verifies then the second half pf December could be exceptionally mild and increasingly wet. Cold prospects could be written off until at least early January.

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Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex

Massive incursion of very mild air deep into Russia probably thawing much of th snowcover there

Posted Image

Very strong intact Vortex driving a vey stable mild pattern for the foreseeable future.

Posted Image

 

No cold for a long time.

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Massive incursion of very mild air deep into Russia probably thawing much of th snowcover there

Posted Image

Very strong intact Vortex driving a vey stable mild pattern for the foreseeable future.

Posted Image

 

No cold for a long time.

Thats disgusting.

The output goes from bad to worse.

The weather can make fools of us all but we really can write off anything wintry (ie snow) this side of christmas.

Sorry if that sounds dramatic but i just dont see how its possible from this setup.

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Posted
  • Location: Clayton-Le-Woods, Chorley 59m asl.
  • Weather Preferences: very cold frosty days, blizzards, very hot weather, floods, storms
  • Location: Clayton-Le-Woods, Chorley 59m asl.

Massive incursion of very mild air deep into Russia probably thawing much of th snowcover there

Posted Image

Very strong intact Vortex driving a vey stable mild pattern for the foreseeable future.

Posted Image

 

No cold for a long time.

No cold? Theres -4 uppers over northern Britain. Thats cold enough to fall as snow over the hills of Scotland and Northern England. Atleast for 2 days though.

Edited by pip22
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Posted
  • Location: hertfordshire
  • Location: hertfordshire

 

Far to much importance is put on the Polar Vortex, your post would suggest to me that without a 'favourable' polar vortex then you can't get cold, which simply isn't true.

I would agree it is not so much the vortex but the depth of cold in the lowerto mid stratosphere and lack of any warming into the strat to promote HLB's.Without such warming you will not displace the vortex let along split it.Therefore any hope of a cold pattern setting up is zero I think.In my prediction for the 13/14 winter I spoke of a piece of the vortex intocentral western Russia and the other into Hudsons bay(southeast Canada) butI was expecting a warmer strat and -AO and NAO which would have been anexcellent pattern for a very cold winter that I was forecasting. Unfortunatelywith a very cold strat and +AO and NAO it is a stinker of a pattern for coldinto the UK.We really need to see a strong Asian mounain torgue that would probably putenough amplitude into the pattern for height rises into Scandinavia and acontinental airflow for Europe and the UK but there is just no sign of this atthe moment.Below is the latest mountain torque plots from the map room.The Asian mountain torque is the red line.post-10506-0-10771600-1386356991_thumb.g
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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL

Massive incursion of very mild air deep into Russia probably thawing much of th snowcover there

Posted Image

Very strong intact Vortex driving a vey stable mild pattern for the foreseeable future.

Posted Image

 

No cold for a long time.

 

Pacific ridge is about to burst out there and send the vortex down our way in the mother of all Northerlies.

 

 

Perhaps.Posted Image

 

Seriously though, saying it doesn't look great is an understatement, but I would not yet completely write December off. It's still too early for that.

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Posted
  • Location: Near Keele, North Staffs
  • Location: Near Keele, North Staffs

Thats disgusting.

The output goes from bad to worse.

The weather can make fools of us all but we really can write off anything wintry (ie snow) this side of christmas.

Sorry if that sounds dramatic but i just dont see how its possible from this setup.

 

I don't think it's dramatic at all HD. We know from past experience that such synoptics can last for anything up to 10 weeks.

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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.

12z ECM has now provided across the board model consistency. We had the Gem teeze on Wednesday, the ECM flutter last night, this evening we have the full set from the big 4 of high drifting around europe and trending south west.

I believe that the situation is now settled for the next 10 days at least, maybe a little inversion chill at 1st next week, before warm wafts of air drift up the Azores.

10 days is the minimum, proberly longer if we take the bias of our natural weather patterns, the pumping vortex, Ec32 update and the law of the sod.

Time for a 4 day time out. I have set myself the challenge of not viewing any models or this place until Tuesday 12z

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Thats disgusting.

The output goes from bad to worse.

The weather can make fools of us all but we really can write off anything wintry (ie snow) this side of christmas.

Sorry if that sounds dramatic but i just dont see how its possible from this setup.

Certainly it looks poor and the ECM has really been dismal in recent weeks at 168hrs onwards, indeed its been even worse than the GFS. Look at last nights 12hrs to see just how all over the place its been at 168hrs onwards.There is an obvious bias in recent years with it overamplifying upstream, unfortunately given the overall trends this might be one post 168hrs that it gets right!

 

I think a lot of patience is going to be needed for coldies, not sure how many survivors we have here from the infamous 88/89 winter debacle, tonights output is disappointing from a cold perspective but still hasn't quite sent me to the trauma unit!

 

One positive is that we can just ignore the ECM 32, so even if that turns up  to pronounce mild we can just view it as just as liable to be wrong as any other output. If my memory serves me that came out with a signal for blocking to the ne only last week,and then before that we were given either blocking to the ne or mid Atlantic high which look like they've imploded. of course if its progging mild it does have a better chance of being correct, that's always more likely to verify but certainly the experience of this winter so far aswell as the last one suggests its a lot of money spent for not much return. Last winters blocking signal to the nw apparently shown by all 51 members caused a lot of discussion in here and that lasted as long as a soufflé before that collapsed!

 

My point being that I don't really have much faith in ensembles run out to that length of time, indeed I'm not that keen on LRF's as a firm believer in chaos theory. Teleconnections wise I did have more time for GP's theories but even then things didn't always go to plan.

Edited by nick sussex
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Posted
  • Location: Near Keele, North Staffs
  • Location: Near Keele, North Staffs

Any chance of analysis, data, quote, reference or indeed anything at all to back up that statement?

 

CH, I'm in touch with a couple of guys who used to be on the Easternwx forums in the US. They are comparing with the PV strength with some of those late 80s/late 90s winters, potentially a record breaking +ve AO in January.

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Posted
  • Location: bingley,west yorks. 100 asl
  • Location: bingley,west yorks. 100 asl

Ah well certainly can't get much worse from a coldie point of view,we have had some cracking winters lately though so maybe jan/feb n march might deliver!?!?

Plenty of great model watching to come so why not take a break if its menotamous?

If your a mildie then enjoy,you guys deserve your choice of weather also.At least living on our beautiful island,we get alittle of everything!

Edited by joggs
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Very few places below average till mid month according to the GFS temperature charts tonight

 

Anomaly

 

Posted Image

 

Seasonal average

 

Posted Image

 

Expected temperatures

 

Posted Image

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Posted
  • Location: Ribble Valley
  • Location: Ribble Valley

Unfortunately to get cold upper air into the UK you need a favourable vortex positioning, you might manage an inversion even with mild uppers under high pressure but that's it. There is no way to transport cold out of the Arctic with the PV stuck to the north, vortex positioning, orientation, whether its split is crucial for cold into the UK. You can manage a decent easterly even with an evil looking PV but this has to be aligned favourably much further to the nw.

 

Simply put if someone said that the PV will remain in one and stuck to the north of the UK near southern Greenland then its easy to make a forecast, indeed if someone drew a global map of the NH  just showing the vortex positioning/ orientation and whether its one or split it would be relatively easy to fill in the gaps with the synoptics.

 

Sadly Barry the PV is the King when it comes to winter patterns.

I disagree as there a number of ways of getting a cold spell to these shore with the PV in it's usual place, of course 9/10 we do need it to play ball.

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Posted
  • Location: Kilmersdon Radstock Somerset
  • Weather Preferences: None Really but a snow lover deep down
  • Location: Kilmersdon Radstock Somerset

Good evening everyone. Here is tonight's rather shorter than usual report on the 12 midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for Friday December 6th 2013.

 

All models through Week 1 show a Westerly flow over the UK at first following a warm front moving East over the North with High pressure close to Southern England. Over the coming days this changes little drifting slowly down into France maintaining relatively mild and rather cloudy weather across the UK with a band of rain and snow clearing East out of Scotland overnight tonight leaving all areas in the same air mass with Western ocasts and hills at risk of drizzle at times with any breaks more likely to the East of hills and in the South. Through next week there may be a period of slightly colder conditions across the South as winds back SE briefly before SW winds look like taking hold again towards the end of the week with mild conditions generally and some rain to Northern and Western extremities.

 

In Week 2 all models that go out that far maintain the status-quo with High pressure to the SE of the UK with SW winds and mild conditions and occasional rain in the North and West with very little signs of change as far as the models can see tonight.

 

The GFS Ensembles continue to show mild weather over the UK for the foreseeable future with few exceptions from the members to this rule. Though dry through Week 1 there seems a slow trend for blocking to the SE to recede somewhat to allow Atlantic troughs and stronger winds to make more progress down over the UK later in Week 2 with some rain for all. However, temperatures will remain distinctly mild feeling despite this.

 

The Jet Stream continues to run NE well to the NW of Britain steering all rain bearing fronts and depressions around the Northern flank of the European High and onward over Northern Scandinavia. There are just the merest hints of it slipping down towards the UK in a NE direction towards the end of week 2 which is reflected by the GFS trend of more rainfall for more areas at the end of the run.

 

In Summary tonight there is nothing to say that hasn't been said already with the Northern arm of the Jet being steered strongly NE well to the NW of Britain around the periphery of a European High which remains dominant throughout the coming two weeks. It's position shuffles around a bit with a slight difference to this morning in that it now looks that less time involving a continental feed is likely from tonight's output suggesting that any cooler and misty days in the South towards midweek could well be short-lived with mild SW winds soon returning with attendant cloud cover but precious little rainfall. As I look towards the position in two weeks time there is little to suggest currently that mild weather won't continue for some time to come after the expiry of the runs, possibly out to Christmas.

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Posted
  • Location: Kesgrave, just East of Ipswich
  • Weather Preferences: April!
  • Location: Kesgrave, just East of Ipswich

By the way, good luck to anyone making predictions for January being very mild based on a couple of days' model runs and some questionable historic parallels.

If they're right I'll be the first to come back on here and congratulate their foresight (or sheer good luck), but I prefer to stick to the school of thought that we can't possibly know, six days into winter, what the weather has planned for the next eight weeks. The weather can, and regularly does, surprise us all, and I would barely rise an eyebrow if the models all switched again soon to a much different outlook when they pick up on an current unknowable.

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Posted
  • Location: Ribble Valley
  • Location: Ribble Valley

CH, I'm in touch with a couple of guys who used to be on the Easternwx forums in the US. They are comparing with the PV strength with some of those late 80s/late 90s winters, potentially a record breaking +ve AO in January.

Could this be down to the exceptional cold pattern over  the States as I would imagine that would fuel any Cyclogenesis exiting the eastern seaboard?

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