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Stratosphere and Polar Vortex Watch

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GFS 12z has the following:

image.thumb.jpg.abd78c9fe83ea1bf6db2f246bd11d130.jpg

Big warming there again, with the +4 isotherm in play.

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2 minutes ago, Mike Poole said:

GFS 12z has the following:

 

Big warming there again, with the +4 isotherm in play.

Yes - a stonker.

image.thumb.png.9838ae16e52d358db58d4cdcbaafd6be.png

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5 hours ago, ArHu3 said:

@sebastiaan1973, we expect too much of a ssw, I checked most of them since 1958 and only 1985 (actually new years eve 1984) and 2012 brought could to our region (I looked at hellmann numbers for de Bilt), most ssw  however were actually preceded by marked cold periods 

I know others have responded on this, but I wanted to add one comment.  This does depend on location, but I think I'm correct in saying that since the turn of 2011, for all the major snow events that have impacted my location in Oxfordshire bar one, a SSW has been implicated!  

If we take as read a warming world, a SSW, for the southern UK at any rate, seems to be rapidly becoming pretty much the only ticket to cold....and yes, it is an uncertain one with no guarantees, 66% success rate...that looks like the reality of the situation.

So to the upcoming SSW, and I'm assuming that this is going to happen now.  This has to be the focus of attention.  The narrative of winter 2019/20 will now be largely determined by what happens after this event, so it is absolutely fascinating, and this thread will busy in the next few weeks.

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3 minutes ago, Mike Poole said:

So to the upcoming SSW, and I'm assuming that this is going to happen now.  

Love the confidence 🙂 , the Met Office weekly show on twitter today noted that their Glosea model isn’t seeing a SSW , only the American model’ is , interesting times 

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I have to say it does look as if there is just the GFS / GEFS going for it to be honest.

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13 minutes ago, Raythan said:

Love the confidence 🙂 , the Met Office weekly show on twitter today noted that their Glosea model isn’t seeing a SSW , only the American model’ is , interesting times 

Confidence?  More flying by the seat of my pants to be honest mate!  The uncertainty is huge!  I'm suspicious of all modelling at the moment, for different reasons, but the trend seems to be towards an SSW.  However, that giant toadstool from my nightmare the other day looms large!!

Edit, to feb's point above, it isn't within the range of the ECM on the Berlin site yet?

Edited by Mike Poole

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7 minutes ago, Raythan said:

Love the confidence 🙂 , the Met Office weekly show on twitter today noted that their Glosea model isn’t seeing a SSW , only the American model’ is , interesting times 

Yes, certainly is interesting. Their words were, '3 runs of the ensemble' - the american model. I do remember a while back a similar thing happening and Fergie saying that nothing was appearing on their model, and to my knowledge, it was correct.

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4 minutes ago, Mike Poole said:

Edit, to feb's point above, it isn't within the range of the ECM on the Berlin site yet?

 

3 minutes ago, Mapantz said:

I do remember a while back a similar thing happening and Fergie saying that nothing was appearing on their model, and to my knowledge, it was correct.

They also could be suggesting it’s not seeing a ‘technical’ SSW but it may well be seeing a warming event ? Was a bit vague in that regard 

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28 minutes ago, Mike Poole said:

I know others have responded on this, but I wanted to add one comment.  This does depend on location, but I think I'm correct in saying that since the turn of 2011, for all the major snow events that have impacted my location in Oxfordshire bar one, a SSW has been implicated!  

If we take as read a warming world, a SSW, for the southern UK at any rate, seems to be rapidly becoming pretty much the only ticket to cold....and yes, it is an uncertain one with no guarantees, 66% success rate...that looks like the reality of the situation.

So to the upcoming SSW, and I'm assuming that this is going to happen now.  This has to be the focus of attention.  The narrative of winter 2019/20 will now be largely determined by what happens after this event, so it is absolutely fascinating, and this thread will busy in the next few weeks.

imageic5gr.png

 

I wished dr. Cohen wouldn't cut off at 0 meridian but above the 3 month temperature anomaly after the 7 most recent major mid-winter ssw's

 

I indeed only checked for my location but if it doesn't get real cold in my location it sure as hell isn't getting cold in the UK (remember february 2012 😜, no one here does, 100-150 km east of London everyone does)

Edited by ArHu3

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15 minutes ago, ArHu3 said:

imageic5gr.png

 

I wished dr. Cohen wouldn't cut off at 0 meridian but above the 3 month temperature anomaly after the 7 most recent major mid-winter ssws

But they aren't the most recent SSWs, the most recent there was 2008 and they are averaged over too long a period to see the impact on UK in my opinion.  Take last year for example, it was widely regarded as a failure but it caused a really good snow event here, just didn't last long!  To clarify, in my post I was talking about the period post 2010.

Edited by Mike Poole

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9 minutes ago, Raythan said:

 

They also could be suggesting it’s not seeing a ‘technical’ SSW but it may well be seeing a warming event ? Was a bit vague in that regard 

Came here to say this too. I think they were talking specifically about a technical SSW, i.e full zonal reversal. 3 GEFS members are going for that which they mentioned.

So the GEFS isn’t really “going for it” either at this stage & they didn’t really go into detail about exactly what GLOSEA was showing. 

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21 minutes ago, Mike Poole said:

Confidence?  More flying by the seat of my pants to be honest mate!  The uncertainty is huge!  I'm suspicious of all modelling at the moment, for different reasons, but the trend seems to be towards an SSW.  However, that giant toadstool from my nightmare the other day looms large!!

Edit, to feb's point above, it isn't within the range of the ECM on the Berlin site yet?

Yes but if the EPS were going for it then the Met Office would not have been quite so bullish, surely they wouldn't go with a seasonal model if the number 1 mid range ensemble suite were showing it within D10-15, GEFS legacy not showing any warming whatsover.

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11 minutes ago, Mike Poole said:

But they aren't the most recent SSWs, the most recent there was 2008 and they are averaged over too long a period to see the impact on UK in my opinion.  I was talking about the period post 2010.

I actually noted dr Cohen that the sample list was in a period of well known mild winters in W.Europe dominated by the Azores/SCEuro high when he put those maps out last winter.

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Also you would think Micheal Ventrice or someone would post up the 10mb eps height and temperature anomalies if they looked interesting.

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5 minutes ago, feb1991blizzard said:

Yes but if the EPS were going for it then the Met Office would not have been quite so bullish, surely they wouldn't go with a seasonal model if the number 1 mid range ensemble suite were showing it within D10-15, GEFS legacy not showing any warming whatsover.

Well you would think so, but these are interesting times, question what do you mean about GEFS legacy?  I wasn't aware there was one, if there is where can you view it?

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2 minutes ago, Mike Poole said:

Well you would think so, but these are interesting times, question what do you mean about GEFS legacy?  I wasn't aware there was one, if there is where can you view it?

image.thumb.png.9b2b2a72f7e1a34636efe78751159111.png

WWW.METEOCIEL.FR

meteociel propose des rubriques météo temps réel, forums, modeles...

 

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7 minutes ago, feb1991blizzard said:

Also you would think Micheal Ventrice or someone would post up the 10mb eps height and temperature anomalies if they looked interesting.

They’re not the worst i’ve ever seen..

6BC7C696-7FE8-4E37-BBA4-1471CF83F0DD.thumb.png.f5989d81d100b46880ad9fac6420e260.pngFC4B71BE-6987-4AF1-93E0-F4E4E747E3CA.thumb.png.7ab283d7d08e91168b9f1476adafe0d3.png

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2 minutes ago, Met4Cast said:

They’re not the worst i’ve ever seen..

6BC7C696-7FE8-4E37-BBA4-1471CF83F0DD.thumb.png.f5989d81d100b46880ad9fac6420e260.pngFC4B71BE-6987-4AF1-93E0-F4E4E747E3CA.thumb.png.7ab283d7d08e91168b9f1476adafe0d3.png

Sorry i meant the EPS.

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10 minutes ago, feb1991blizzard said:

image.thumb.png.9b2b2a72f7e1a34636efe78751159111.png

WWW.METEOCIEL.FR

meteociel propose des rubriques météo temps réel, forums, modeles...

 

I think you are off on a tangent with that one, feb, news to me I've never even seen it on Meteociel, but the text at the bottom gives it away...it's from a version of the model from 2015, run 0z for reasons of comparison, nothing to do with the current versions, as I believe the GEFS now is at it has been, i.e. Not upgraded to the FV3.  If anyone knows better please chip in!

 

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4 minutes ago, Mike Poole said:

I think you are off on a tangent with that one, feb, news to me I've never even seen it on Meteociel, but the text at the bottom gives it away...it's from a version of the model from 2015, run 0z for reasons of comparison, nothing to do with the current versions, as I believe the GEFS now is at it has been, i.e. Not upgraded to the FV3.  If anyone knows better please chip in!

 

Yes but even the 2015 version is still good enough as a cross reference point, the GEFS / GFS haven't improved so much in the last 4 years that makes it completely outdated, the point is its another model showing bugger all - it looks to me like its GEFS / GFS v every other model.

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5 minutes ago, feb1991blizzard said:

Yes but even the 2015 version is still good enough as a cross reference point, the GEFS / GFS haven't improved so much in the last 4 years that makes it completely outdated, the point is its another model showing bugger all - it looks to me like its GEFS / GFS v every other model.

Given GEFS supposedly hasn't changed that much since 2015, and with proviso that it hasn't been replaced by the FV3 core - I don't think it has but not 100% sure, given that, I don't think the chart you quoted is credible given other output...and it isn't GFS and GEFS against every other model, the GEM ensembles are on board, and us mere mortals don't have access to the other ones at that range.

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37 minutes ago, Mike Poole said:

I think you are off on a tangent with that one, feb, news to me I've never even seen it on Meteociel, but the text at the bottom gives it away...it's from a version of the model from 2015, run 0z for reasons of comparison, nothing to do with the current versions, as I believe the GEFS now is at it has been, i.e. Not upgraded to the FV3.  If anyone knows better please chip in!

According to the agenda for the forthcoming Scientific Organisation AGU100 meeting in San Fransisco, 9th - 13th December, we've got to wait until Q4 2020 for the GEFS to be upgraded:

Following the deterministic global model upgrade, NCEP is planning on implementing the Global Ensemble Forecast System (GEFS v12) in Q4FY20. Apart from using the same FV3 based global model, GEFSv12 will include higher horizontal resolution, increased number of ensembles, advanced stochastic physics for representation of forecast uncertainty, coupling to wave ensembles, and, for the first time, extending the forecast length to 35 days for providing operational forecast guidance for weeks 3&4. GEFSv12 also comes with 20-year reanalysis and 30-year reforecast data for calibration of forecast products.

https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/490779

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2 hours ago, ArHu3 said:

imageic5gr.png

 

I wished dr. Cohen wouldn't cut off at 0 meridian but above the 3 month temperature anomaly after the 7 most recent major mid-winter ssw's

 

I indeed only checked for my location but if it doesn't get real cold in my location it sure as hell isn't getting cold in the UK (remember february 2012 😜, no one here does, 100-150 km east of London everyone does)

I’m suspicious of any 2 month average chart in terms of usefulness....but one thing is clear from all those charts - cold air spills into the 2 significant northern hemisphere continents, and this provides a source that can be tapped into. And returning to an earlier point - for the UK we need to stop the Atlantic in order to do this, and this requires a weakening of the westerly momentum at 60-65N (and higher). Cold spells can happen with other major forcings (eg very strong Nina Dec10) but of all potential forcings a SSW offers us the most dramatic chance of an impact on the default circulation. I can understand the frustration at the lack of a clear and obvious correlation, but at some point we have to apply conceptual understanding as much as statistical analysis and an SSW offers opportunity even if it doesn’t offer a guarantee.

Edited by Catacol

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Whatever we think about GEFS bias this is quite an impressive grouping and trend...

image.thumb.png.64719b93af8be0553d885e71efd34316.png

Edited by Catacol

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Got a feeling going by the models that there will be an SSW but not sure on the type which could be important, i just think the GEFS / GFS may be a bit early with it, i reckon a technical SSW but no earlier than 15th December.

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