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Model output discussion - cold spell approaching?


Message added by Paul,

Please only use this thread to comment specifically about the model output. If you want to have a moan, ramp or to chat more generally about the models, the weather and so on, please use the winter chat and moans thread

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Posted
  • Location: Bournville Birmingham
  • Weather Preferences: Hot n cold
  • Location: Bournville Birmingham
1 hour ago, Ice Day said:

The Mean is quite an improvement vs the 6z at 168.

A small step forward and maybe we've stopped the rot from this mornings rubbish?

 

Screenshot_20210113-165147_Meteociel.jpg

You're kidding! Back to square one in the morning

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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.
4 minutes ago, Griff said:

Not sure it will end as well as gem

ECH1-192.gif

gemnh-0-192.png

Remarkably similar again considering day 8 and two different models.. I felt on this 192 ecm looked less messy than gem...

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Posted
  • Location: Near Gouda, Holland. 6m Below Sea Level.
  • Weather Preferences: Sun, snow, ice. Very hot or very cold.
  • Location: Near Gouda, Holland. 6m Below Sea Level.

EC doesn't want to play with the other models.

Same issue as yesterday and this morning. The low over Newfoundland is more reluctant to move East, therefore WAA happens too far West, setting up the High too far West.

UKMO and GFS were just far enough East.

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Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
5 minutes ago, Mike Poole said:

No it doesn’t, T216:

CBCA252B-AB69-45F3-81BC-F86882A4DB6B.thumb.png.8aefa690cda0dd48d43f2b77fcbe6d8c.png

...and i have to ask what is causing these lows to blow up like this on several runs today (mostly on the morning set), there doesn’t seem any driver for this to happen with the Atlantic in deadly slumber.  I’m going out on one here and say it is model error in the face of large uncertainties. 

As much as I'd love to be injecting optimism and good news here, the GFSP was showing this at times over the last week, having trended away from the good stuff  

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
25 minutes ago, Tim Bland said:

ECM has a some snow in the south East sat but generally makes little of anything wintry, unlike Aperge and UKV. Has anyone seen latest UKV for tomorrow and Sat? 

C849A3BB-792C-4703-A128-18B14EF9F539.jpeg

EEF042D9-FDCE-4269-B52A-EA14A6C4F91F.jpeg

20CBE048-A3BF-4112-84B7-B9502D457295.jpeg

The ECM is less interested in disrupting energy se wards .  The UKMO is more bullish about that . The day 3 fax chart looks interesting . Let’s hope the ECM is wrong as it delivers not much on Saturday and then to add insult to injury its later output is to put it mildly crxp! 

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
Just now, Griff said:

As much as I'd love to be injecting optimism and good news here, the GFSP was showing this at times over the last week, having trended away from the good stuff  

Oh yes, it has shown up on plenty of runs, sometimes you just have to make a bet that what is shown is the wrong solution, is all.  

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

Yet another negative we have seen the last couple of days is for the arctic high to move E rather than S toward Greenland to help us out through the mid term. In general terms this also means the coldest air is directed toward Siberia rather than through Scandi toward us.

 

ECM Arctic high 192

ECH1-192.GIF?13-0

850's today V 48 hours ago.

ECH0-192.GIF?13-0ECH0-240.GIF?12

I'm not talking about the difference in cold over the UK but how the deep Arctic cols if further SW heading toward Scandi to begin with to tap into whereas now it is heading for Siberia.

So basically every driver of the pattern for deep cold has been modified in the opposite direction we would like from the Atlantic low to the Atlantic ridge to the arctic high to the Scandi trough, the UK Winter curse.

This leaves us fighting for scraps and looking back out toward day 10 charts.

At least this afternoon saw some improvement from this morning but the cold spell is going to be hard to land.

 

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

If the gfs 12z (outlier late on) op had not existed then the ecm would be along the lines we were expecting, as per the gfs 06z and the gefs 12z mean:

ecm 12z op>ECH1-216.thumb.gif.8eca7bb9e0b52c74a2b646b024b7cb5e.gif 

gfs 06z op>gfsnh-0-204.thumb.png.3c7898e293aecd2d4fdc658bbe6b6026.png

What the ecm shows is a variation on that theme on the gefs 12z ens members. Not pretty knowing where the gfs 06z went in FI. Funny enough the ecm 0z was along the line of the gfs 12z op so it is probably just running through its clusters like the gfs. We will eventually get agreement but it will not be on the 12z suites. Confidence is low but not a lost cause just yet.

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

I like the JMA at T192:

98CE38B2-F91B-49C7-B375-AF447DB44E71.thumb.gif.bcbb1359df6b4857840e9786a006e713.gif

Nothing too far west about this run, and possibilities going forward, could it link with scandi here?  

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Posted
  • Location: Maldon, Essex
  • Location: Maldon, Essex

Again, it's best not to look past T96.

Genuine questions:

1. If the Atlantic is so dead, why are we having all these issues with low pressures coming at us. What is this talk of recersal?

2, Is the UK a statistical anomaly, since it requires more luck than anywhere else of a similar latitude to get cold in?

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Posted
  • Location: Leicester
  • Location: Leicester
7 minutes ago, nick sussex said:

The ECM is less interested in disrupting energy se wards .  The UKMO is more bullish about that . The day 3 fax chart looks interesting . Let’s hope the ECM is wrong as it delivers not much on Saturday and then to add insult to injury its later output is to put it mildly crxp! 

Ecm has gone more towards ukmo than the other way around last couple if days so i think its playin catch up!!

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL

Even with crap uppers ECM 12z is quite wintry for northern half of country. What I would say there is something for someone.

83991A23-652A-465E-A59E-A4C33C45C194.thumb.png.116a56d067de1c55ceedd15172098413.png

 

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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level
16 minutes ago, Mike Poole said:

No it doesn’t, T216:

CBCA252B-AB69-45F3-81BC-F86882A4DB6B.thumb.png.8aefa690cda0dd48d43f2b77fcbe6d8c.png

...and i have to ask what is causing these lows to blow up like this on several runs today (mostly on the morning set), there doesn’t seem any driver for this to happen with the Atlantic in deadly slumber.  I’m going out on one here and say it is model error in the face of large uncertainties. 

Hit the nail on the head there Mike my son.. The models just can't handle the state of such a chaotic Atmosphere... They get to a few days out and lose there way, and kind of just start reverting back to some kind of climate norm... Like you say the Atlantic is a dead duck and there just ain't the energy for these scenarios being flagged up by ECM.. 

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Posted
  • Location: Home: Chingford, London (NE). Work: London (C)
  • Weather Preferences: Winter: cold and snowy. Summer: hot and sunny
  • Location: Home: Chingford, London (NE). Work: London (C)
4 minutes ago, Djdazzle said:

 

2, Is the UK a statistical anomaly, since it requires more luck than anywhere else of a similar latitude to get cold in?


Pretty much! At our latitude, it’s really only NW Europe and the Pacific NW (Seattle, Portland, Vancouver) etc that have a temperate maritime climate. So many things have to fall into place for us to tap into deep cold compared to most other parts of the world at our latitude. 

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
13 minutes ago, Djdazzle said:

Again, it's best not to look past T96.

Genuine questions:

1. If the Atlantic is so dead, why are we having all these issues with low pressures coming at us. What is this talk of recersal?

2, Is the UK a statistical anomaly, since it requires more luck than anywhere else of a similar latitude to get cold in?

Well we wouldn’t be having the prospect of Atlantic/Greenland ridging, you wouldn’t see that Arctic high either but it doesn’t appear to be near enough to exercise much influence. Cold cyclonic flows actually can be quite exciting just whether polar air can dig far enough south or it’s a cold rain washout. We talk about all the teleconnections but sometimes everything can align.. all we need is a bit of a luck it’s true.
 

B870BDD0-C0A1-4AA3-AAA8-95B49B97B278.thumb.png.cd9075fe7282f3e2f449f04de28c4968.png

 

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Posted
  • Location: Frome 330ft ASL
  • Weather Preferences: Most(see in interests section.)
  • Location: Frome 330ft ASL
5 minutes ago, chris55 said:

Do we have a clear trend beyond day 5? Not really.

Do we have a clear forecast up to day 5? Not really.

Do we have a clear trend in the extended range? Again not really (although you could argue for a colder pattern due to the SSW)

So, what can we deduce from these statements? (My home schooling head is on)

Answer; The data is producing an unsatisfactory level of consistency to make any form of firm judgement that would be more than 60% probability so no definite conclusion can be made.

More runs needed

Absolutely spot on Chris, 

Charts on this run look good but as we know all can change in the flick of a switch. GFS definite confused.com...

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Posted
  • Location: East Ham, London
  • Location: East Ham, London

Evening all

A damp old day in lowland East London but I was struck by the lack of wind (no giggling in the cheap seats, please) so whatever was happening was going to keep happening and pretty slowly.  I'll leave others to muse on the immediate fun and games - as always, I'm expecting nothing in my part of the world but beyond the immediate, there were strong signals for a colder evolution into the final third of the month.

Last night's Parallel was the exception and this was due to maintaining strong heights over the Mediterranean which prevented the trough moving too far south and leaving southern Britain in a very mild SW'ly. Keeping heights low to the south is as important to the evolution of cold as building heights to the north west or north east.

Anyhoo, let's see what tonight's soft, strong and highly absorbing pictures tell us.

12Z GEM: T+120 takes us to next Monday at which time the British isles is in a north-west to westerly flow between an area of LP over the Faeroes and an HP centred over Iberia. Upstream, heights extend to Greenland with the nest Atlantic LP further south at this time. 850s below -4 in the north but zero to -4 in the south with milder air close by to the west. From there, the LP to the north sinks south and phases with part of the Atlantic trough forming a new elongated trough from the British Isles east to the Baltic. A slack flow over the British isles at T+180 with heights building south east from Greenland and the next LP far to the west. Any positive uppers are along Channel coasts with colder air moving down from the north with uppers of -4 to -8. By T+240, the trough extends over much of Europe with main centres over the Baltic, Northern Britain and the Northern Adriatic. A cyclonic flow extends over the British Isles back to an elongated Atlantic trough but I note a ridge moving into Iberia trying to push the jet back north closer to the British Isles by this time. Heights persist over Greenland. Colder air has pushed down from the north with uppers of -8 or below but by T+240 these have moderated slightly.

image.thumb.png.b5592a8e8cd8f7655896c7572fe97ae5.pngimage.thumb.png.39e11489f788e7ae6f510745ec7de589.pngimage.thumb.png.a6dd76a5b9423ed6da303362cdcbc455.png

12Z GFS OP -not bad from GEM - I'll give it a 7/10 as I'm worried about heights returning to Iberia but on to the GFS OP. At T+120 some subtle differences from GEM. The Atlantic LP is closer and deeper than on GEM while the HP to the south is weaker. The LP to the north extends to a second centre over northern Scandinavia. Uppers of -4 to -8 over the British Isles by this time with milder air approaching from the west and the coldest air over south-east Europe. The Atlantic LP moves toward the British Isles, phases with the LP to the north and deepens to be over Ireland by T+180. Heights persist to the north-west and over south-eastern Europe. Milder air has pushed through the British Isles but colder air has pushed south to the west of Ireland. From there, the LP moves across the British isles and then SE into Europe and by T+240 is over Italy with a secondary centre over the Low Countries. With heights persisting to the west, a NE'ly flow is drawn south across the British Isles. Colder air has therefore pushed south with uppers of -4 to -8 generally, coldest in the west.

image.thumb.png.aeee6c7ceb2a7993b97e6b7ea95321b2.pngimage.thumb.png.99fc6c39600d924422275f28ad13f198.pngimage.thumb.png.9322d5491601307da35578b80dddbb37.png

12Z Parallel - well, OP got there though it wasn't pretty but that looks a more solid and longer-lasting evolution (he said hopefully). On then to Parallel - will it be the jewel in the crown or the fly in the ointment (as it was last evening)? Again, subtle differences by T+120. The HP to the south extends from the Azores through Iberia to France. The Atlantic LP to the west seems a smidge further north than on the OP while the LP to the north seems weaker as do the heights around Greenland. Areas of -4 to -8 remain over the British Isles with milder air encroaching from the west. From there, the Atlantic LP and the LP to the north phase and develop a new deep LP to the north-east of the British Isles while heights extend south east from Greenland. A new Atlantic LP sits far to the west but the heights to the north haven't quite split the trough by T+180. A NW'ly air flow covers the British Isles and colder air is moving down leaving the positive uppers combined to the south east and uppers of -4 to -8 moving into northern and western areas. Moving on and the battleground develops with initially cold air over the British Isles but a new Atlantic LP deepens far to the west but as it goes nowhere it throws heights up into Iberia which kick the jet north and looks as though it will cut any cold spell short. Uppers remain -4 to -8 over most of the British Isles by T+240 but milder air isn't far away.

image.thumb.png.6eb041af2356230fdf4a75681593466b.pngimage.thumb.png.6ea8a2a85f22db42978fbf924b80258f.pngimage.thumb.png.016cf5572d8b6c94523668aef9549642.png

12Z ECM - heights to the south look like they will cut any cold spell short by sending the jet back north and leaving the British isles on the warm side. Finally, the Europeans for the evening.  Not too surprising at T+120 with negative uppers remaining over the British Isles though with milder air again threatening from the west. At T+192 ECM resembles GFS Parallel but with a simpler and deeper LP to the east Of Scotland once the phasing of the troughs has occurred. Colder air has swept back south and east by T+192 with uppers of -4 to -8 generally. The controlling trough remains in situ but the interaction between the cold air and the warm air along the pressure gradient leads to the formation of a strong secondary feature which deepens intensely to be over north-west France by T+240. Milder air is close to southern coastal areas in the warm sector of the LP but it remains colder elsewhere. 

image.thumb.png.023855cc9aa743d9084a283f09e2acf7.pngimage.thumb.png.050ec655f67eab466b547db71b2dc04b.pngimage.thumb.png.f2c6088eae2770a35dced6089d7796ce.png

Neither ECM nor Parallel give much optimism to the longevity of any cold spell with the Atlantic threatening to move in and the jet moving back north.

Let's see what further FI has to offer from GFS OP and Parallel:

image.thumb.png.74d0a63856aa4fbc343344d6558467c4.pngimage.thumb.png.3032d04b1f56e30c41bfee0038ffb0db.png

image.thumb.png.5220f1ed3862362c7eff454ded98fd21.pngimage.thumb.png.dbbecb289b3a0803cc79bb2238295134.png

The very epitome of chalk and cheese - GFS OP you'd want to take home to meet the parents, Parallel you'd want to avoid at all costs. Control has a cold spell and interestingly at the far end of FI brings in heights to the north-east but turns milder for the British Isles.

On then to the 10 HPA charts - OP keeps a strong PV despite almost continuous warming from the Siberian side and Parallel is similar as is Control so the PV re-strengthens despite the continuous warming - okay?

Conclusion: a step back for cold fans tonight. The hint picked up by Parallel last evening continues this evening though not to the same extent though it's a concern ECM is tempted by it. GFS OP is a superb run for cold and snow fans but it looks as much an outlier as Parallel. There's an evolution to something cold from the north or north-east but the severity and duration remain far from resolved. To be fair, there's no sign of a raging PV anywhere tonight so the question becomes whether heights over southern Europe can be suppressed long enough to allow the cold to take hold or will the battleground scenario be the answer which may be good for the north but not for the south? 

 

image.png

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Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)

UKMO/ Fax looks good for Eastern Areas sat. Like tomorrow’s event has shown - I wouldn’t bet against a further shift though 

1AFEDEFB-3B98-46C0-81AA-FAC4EC220A33.jpeg

E189C46D-5ADC-4E4D-BB5F-C75EF8C1B685.jpeg

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