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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: St Albans, 95m asl
  • Location: St Albans, 95m asl
1 hour ago, karyo said:

So basically that's even worse news for our winter. 

I think it’s more just a general discussion to be fair - we won’t know for a few more months whether we are actually seeing a failure to downwell or not.

I’m sure if we were monitoring things this closely back in 08/09 we might be wondering whether the same was happening then too:

https://www.esrl.noaa.gov/psd/data/correlation/qbo.data

The phase change of the QBO is not a linear phenomenon - we’ve seen a few years ago how there can be a miscue of the usual W-E-W-E pattern, but on the scale of month to month we have historically seen some variance in the 30mb series.

The truth is, we simply won’t know until early next year - but to finish on an optimistic note, I remember a certain February 2009 cold spell....

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
4 hours ago, karyo said:

So basically that's even worse news for our winter. 

After last year, I for one will not be getting excited about winter this year, at least not until juicy charts come into the 72 hour time frames!  As it is, I don’t think the prospects for a cold winter are good this year anyway.

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)
9 minutes ago, Don said:

After last year, I for one will not be getting excited about winter this year, at least not until juicy charts come into the 72 hour time frames!  As it is, I don’t think the prospects for a cold winter are good this year anyway.

Agreed! Everything has to fall in to right place for a cold spell to develop and even then it can implode just a few days before it starts.

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)
3 hours ago, snowking said:

I think it’s more just a general discussion to be fair - we won’t know for a few more months whether we are actually seeing a failure to downwell or not.

I’m sure if we were monitoring things this closely back in 08/09 we might be wondering whether the same was happening then too:

https://www.esrl.noaa.gov/psd/data/correlation/qbo.data

The phase change of the QBO is not a linear phenomenon - we’ve seen a few years ago how there can be a miscue of the usual W-E-W-E pattern, but on the scale of month to month we have historically seen some variance in the 30mb series.

The truth is, we simply won’t know until early next year - but to finish on an optimistic note, I remember a certain February 2009 cold spell....

That's true but any delay at this stage is not what we want to see. Let's hope that things will move in the right direction with the next update.

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
20 minutes ago, karyo said:

That's true but any delay at this stage is not what we want to see. Let's hope that things will move in the right direction with the next update.

I couldn’t access that twitter article on my phone.  Are they taking about the possibility of another EQBO failure like what happened in 2016?

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Posted
  • Location: Exeter, Devon, UK. alt 10m asl
  • Location: Exeter, Devon, UK. alt 10m asl
7 hours ago, snowking said:

I think it’s more just a general discussion to be fair - we won’t know for a few more months whether we are actually seeing a failure to downwell or not.

I’m sure if we were monitoring things this closely back in 08/09 we might be wondering whether the same was happening then too:

https://www.esrl.noaa.gov/psd/data/correlation/qbo.data

The phase change of the QBO is not a linear phenomenon - we’ve seen a few years ago how there can be a miscue of the usual W-E-W-E pattern, but on the scale of month to month we have historically seen some variance in the 30mb series.

The truth is, we simply won’t know until early next year - but to finish on an optimistic note, I remember a certain February 2009 cold spell....

If we were to go on a simple matching of pattern then the current cycle to me most closely resembles 1998/1999 so if were to follow then it would be next winter and into spring 21 before we have a Easterly direction below the 50 hPa 

 

EExghEVW4AAqETx.jpg

Edited by swebby
correcting jpg format
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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
3 hours ago, Don said:

I couldn’t access that twitter article on my phone.  Are they taking about the possibility of another EQBO failure like what happened in 2016?

Probably just a panic, a look at the standardised data since 1979 shows that it could be anywhere from 4-11 months before we see negative values even exempting the missed 2016 cycle. It's simply that people were overly giddy. 

2 minutes ago, swebby said:

If we were to go on a simple matching of pattern then the current cycle to me most closely resembles 1998/1999 so if were to follow then it would be next winter and into spring 21 before we have a Easterly direction below the 50 hPa 

EExghEVW4AAqETx.jpg_largeUnavailable

A look at Neutral vs SSW events suggests that the incidence of warmings is still fairly high and from our current level we are looking at >1 values for only another 1-5 months so i would not be overly concerned. 

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)

Southern Hemisphere SSW off the scale at 10 hpa.

pole10_sh.thumb.gif.2578b3d25957538f651faa22d747c66f.gif

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
1 hour ago, Allseasons-si said:

Southern Hemisphere SSW off the scale at 10 hpa.

pole10_sh.thumb.gif.2578b3d25957538f651faa22d747c66f.gif

Well, that’s certainly interesting whether it has an influence on the northern hemisphere or not.

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Posted
  • Location: Camborne
  • Location: Camborne

This was first published at the end of last year but in case anyone missed it

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

Quote

Abstract

El Niño and La Niña events in the tropical Pacific have significant and disrupting impacts on the global atmospheric and oceanic circulation. El Niño Southern Oscillation (ENSO) impacts also extend above the troposphere, affecting the strength and variability of the stratospheric polar vortex in the high latitudes of both hemispheres, as well as the composition and circulation of the tropical stratosphere. El Niño events are associated with a warming and weakening of the polar vortex in the polar stratosphere of both hemispheres, while a cooling can be observed in the tropical lower stratosphere. These impacts are linked by a strengthened Brewer‐Dobson circulation. Anomalous upward wave propagation is observed in the extratropics of both hemispheres. For La Niña, these anomalies are often opposite. The stratosphere in turn affects surface weather and climate over large areas of the globe. Since these surface impacts are long‐lived, the changes in the stratosphere can lead to improved surface predictions on time scales of weeks to months. Over the past decade, our understanding of the mechanisms through which ENSO can drive impacts remote from the tropical Pacific has improved. This study reviews the possible mechanisms connecting ENSO to the stratosphere in the tropics and the extratropics of both hemispheres while also considering open questions, including nonlinearities in the teleconnections, the role of ENSO diversity, and the impacts of climate change and variability.

Plain Language Summary

El Niño and La Niña events, the irregular warming and cooling of the tropical Pacific that occurs every couple of years, have disrupting impacts spanning the entire world. These remote impacts, so‐called “teleconnections”, also reach the stratosphere, the layer of the atmosphere starting at around 10 km above the Earth's surface. El Niño leads to a warming of the stratosphere in both hemispheres, while the lower tropical stratosphere cools. These signatures are linked by a strengthened stratospheric circulation from the tropics to the polar regions. El Niño also leads to more frequent breakdowns of the stratospheric polar vortex, a band of strong eastward winds in the polar stratosphere. For La Niña, these effects tend to be opposite, though they are not always robust, suggesting nonlinear or nonstationary effects, long‐term variability, and trends in the teleconnections. The observational data record is not yet long enough to make conclusions with certainty, and models that try to reproduce the teleconnections indicate that teleconnections might be more linear than the limited number of observations indicate. Further research will be needed to separate the El Niño and La Niña teleconnections from other effects and to determine to what extent nonlinearity and nonstationarity are indeed present.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000596

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

"Arctic Oscillation and Polar Vortex Analysis and Forecasts" 

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

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Posted
  • Location: Strathblane/Killearn nr Glasgow
  • Location: Strathblane/Killearn nr Glasgow

I know we are only at the end of September and October just round the corner less than 2 days away but I wonder if chionomaniac would like to give us some early indications as to whether or not he thinks September this year is similar to back in 2009 or 2010? Would anyone perhaps less knowledgeable when it comes to the stratosphere and autumn patterns like to have a go at answering my question? 

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Posted
  • Location: Wakefield, West Yorkshire
  • Location: Wakefield, West Yorkshire
3 hours ago, Frozen Britain said:

I know we are only at the end of September and October just round the corner less than 2 days away but I wonder if chionomaniac would like to give us some early indications as to whether or not he thinks September this year is similar to back in 2009 or 2010? Would anyone perhaps less knowledgeable when it comes to the stratosphere and autumn patterns like to have a go at answering my question? 

Tagged him so he sees it! @chionomaniac

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

^^

Wrong thread but if these continue it would have effects on the Strat, stopping strong zonal flow propagating down - just too early yet to get to excited.

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Posted
  • Location: Camborne
  • Location: Camborne

Tropospheric and Stratospheric Causal Pathways Between the MJO and NAO

Quote

Abstract

Previous work has shown that the Madden‐Julian Oscillation (MJO) can influence the North Atlantic Oscillation (NAO) via a Rossby wave teleconnection that propagates through the troposphere (i.e., a tropospheric pathway). In addition, recent work suggests that the MJO can influence the stratospheric polar vortex, which is also known to influence the tropospheric NAO—thus, there likely exists a stratospheric pathway for MJO influence as well. Here, we apply two methods to shed more light on the pathways linking the MJO to the NAO. First, we use a traditional approach in climate science based on analyzing conditional probabilities. Second, we use methods from causal discovery theory based on probabilistic graphical models. Together, these two analysis approaches reveal that the MJO can impact the NAO via both a tropospheric and stratospheric pathway. The stratospheric pathway is shown to come about in two ways: First, both methods show that the MJO itself influences the strength of the stratospheric polar vortex on a timescale of ∼10 days, and then 5 days later the vortex can drive changes in the NAO. Second, the state of the stratospheric polar vortex acts to condition the NAO to be conducive (or not) to MJO influence. When the vortex is in a state that opposes the expected NAO response to the MJO, we find little influence of the MJO on the NAO, however, when the vortex supports the expected NAO response, the NAO is up to 30% more likely to be in a particular state following active MJO periods.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031024

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

Nonlinear response of Northern Hemisphere stratospheric polar vortex to the Indo–Pacific warm pool (IPWP) Niño

https://www.nature.com/articles/s41598-019-49449-7#disqus_thread

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
Posted
  • Location: Poole, BH14
  • Location: Poole, BH14
Posted
  • Location: Netherlands
  • Location: Netherlands

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019JD030903

Abstract Snow initialization has been previously investigated as a potential source of predictability atthe subseasonal‐to‐seasonal (S2S) timescale in winter and spring, through its local radiative,thermodynamical, and hydrological feedbacks. However, previous studies were conducted with low‐topmodels over short periods only. Furthermore, the potential role of the land surface‐stratosphere connectionupon the S2S predictability had remained unclear. To this end, we have carried out twin 30‐memberensembles of 2‐month (November and December) retrospective forecasts over the period 1985–2016, witheither realistic or degraded snow initialization. A high‐top version of the Norwegian Climate PredictionModel is used, based on the Whole Atmosphere Community Climate Model, to insure improved couplingwith the stratosphere. In a composite difference of high versus low initial Eurasian snow, the surfacetemperature is strongly impacted by the presence of snow, and wave activityfluxes into the stratosphere areenhanced at a 1‐month lag, leading to a weakened polar vortex. Focusing further on 7 years characterized bya strongly negative phase of the Arctic Oscillation, we find a weak snow feedback contributing to the maintenance of the negative Arctic Oscillation. By comparing the twin forecasts, we extracted the predictive skill increment due to realistic snow initialization. The prediction of snow itself is greatly improved, andt here is increased skill in surface temperature over snow‐covered land in the first 10 days, and localized skillincrements in the mid‐latitude transition regions on the southernflanks of the snow‐covered land areas, at lead times longer than 30 days.

Edited by sebastiaan1973
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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

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