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Stratosphere and Polar Vortex Watch


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Posted
  • Location: Efford, Plymouth
  • Weather Preferences: Misty Autumn Mornings, Thunderstorms and snow
  • Location: Efford, Plymouth

    From memory wasnt every long range totally Westerly zonal last year? Berlin, French, Bejing, Cansips. It was just one after another with low Pressure to our North or over us. And then it verified...

    I've seen a chart showing that the polar vortex isnt projected to be as strong through the end of Autumn into December which may have a good bearing.  Any ideas when we last had a very weak polar vortex? 

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    Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

    so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

    For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

    Posted Images

    Posted
  • Location: st albans
  • Location: st albans
    44 minutes ago, philglossop said:

    From memory wasnt every long range totally Westerly zonal last year? Berlin, French, Bejing, Cansips. It was just one after another with low Pressure to our North or over us. And then it verified...

    I've seen a chart showing that the polar vortex isnt projected to be as strong through the end of Autumn into December which may have a good bearing.  Any ideas when we last had a very weak polar vortex? 

    As we headed into winter 2018/19, the pv was pretty disorganised and weak. by mid December it wasn’t 

    and last autumn, the forecasts were for a strong winter pv but I don’t recall it being a leviathan late autumn and into December  - it was as winter progressed though ! 

    The point here is a weakish vortex as we head into December is no guarantee of anything .......it can ramp up v quickly indeed 

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    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK
    1 hour ago, bluearmy said:

    As we headed into winter 2018/19, the pv was pretty disorganised and weak. by mid December it wasn’t 

    and last autumn, the forecasts were for a strong winter pv but I don’t recall it being a leviathan late autumn and into December  - it was as winter progressed though ! 

    The point here is a weakish vortex as we head into December is no guarantee of anything .......it can ramp up v quickly indeed 

    image.thumb.png.ed96c2436ee5df2ed362515024033feb.png

    Agreed - whatever the PV may be up to at present has no bearing on what might happen in the weeks or months later. As this chart above shows, in Dec/Jan 2017/18, the PV was much stronger than average....a few weeks and a SSW later, and the 'beast from the east' cold spell was here.

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
    12 hours ago, mb018538 said:

    image.thumb.png.ed96c2436ee5df2ed362515024033feb.png

    Agreed - whatever the PV may be up to at present has no bearing on what might happen in the weeks or months later. As this chart above shows, in Dec/Jan 2017/18, the PV was much stronger than average....a few weeks and a SSW later, and the 'beast from the east' cold spell was here.

    Recent years have brought rather dis-organised PV development as we enter December,  with some colder more settled weather in November and the very start of Dec only for things to then turn markedly unsettled. Last year a case in point, 2018 also, 2013 and 2016 also brought quite cold settled weather at times in November.

    The only year bucked the trend was 2017 which also brought quite cold settled conditions in November, but courtesy of more of a northerly airflow rather than anticyclonic.

    This isn't a winter watch post, but interesting to note Novembers with northerly episodes such as 1995, 1996, 2001, 2005, 2008, 2010, 2012 and 2017 were all followed by at least one bout of cold weather in December, in some of these years notable and long lasting. Anticyclonic spells as have occurred in recent Novembers have not done the same. More noteworthy is how the jet is behaving in November I feel, a buckled flow may suggest business not normal.

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    Posted
  • Location: Netherlands
  • Location: Netherlands
    On 31/08/2020 at 13:36, SqueakheartLW said:

    Apart from that great big red blob just off the coast of the US again

    The positive MSLP just south of Alaska and the Aleutian Islands reduces the strenght of the climatological cyclone and, therby, reduces the amplitude of planetary waves propagating upwards into the stratosphere (Source: predictability of European winter 2019/2020: IPO impacts on the NAO)

     

    Edited by sebastiaan1973
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    Posted
  • Location: Netherlands
  • Location: Netherlands

    https://iopscience.iop.org/article/10.1088/1748-9326/ab0385

    Stratospheric initial conditions provide seasonal predictability of the North Atlantic and Arctic Oscillations.

    Abstract

    The North Atlantic Oscillation (NAO), the regional manifestation of the Arctic Oscillation (AO), dominates winter climate variability in Europe and North America. Skilful seasonal forecasting of the winter NAO/AO has been demonstrated recently by dynamical prediction systems. However, the role of initial conditions in this predictability remains unknown. Using a latest generation seasonal forecasting system and reanalysis data, we show that the initial upper stratospheric zonal wind anomaly contributes to winter NAO/AO predictability through downward propagation of initial conditions. An initial polar westerly/easterly anomaly in the upper stratosphere propagates down to the troposphere in early winter, favoring a poleward/equatorward shift of the tropospheric mid-latitude jet. This tropospheric anomaly persists well into the late winter and induces the positive/negative phase of NAO/AO in the troposphere. Our results imply that good representation of stratospheric initial condition and stratosphere-troposphere coupling in models is important for winter climate prediction.

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    Posted
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
    3 hours ago, sebastiaan1973 said:

    The positive MSLP just south of Alaska and the Aleutian Islands reduces the strenght of the climatological cyclone and, therby, reduces the amplitude of planetary waves propagating upwards into the stratosphere (Source: predictability of European winter 2019/2020: IPO impacts on the NAO)

     

    I believe there is a certain path developing where this winter is heading, a while back there was an interesting twitter exchange that we had with Matt Hugo and Anthony Masiello about the Aleutian high that is going to be present this winter as we see the trend of Nina to be now more in moderate strength then a weak affair. The first in line will be the Pacific jet pattern-behavior and ability of its poleward trajectory that can cause downstream Rossby wave train and favorable wave2 tropospheric configuration to keep the lid on perhaps unfavorable top to bottom stratospheric configuration akin to Nov/Dec 2010. Here probably lies the notion of front loaded winter as a lack of Aleutian low top to bottom stratospheric weakening isn't going to happen as also QBO at 1hPa will be in westerly phase. For followers with advanced knowledge these tweets can be seen as self explanatory and visionary accustomed to Masiello himself.   

    Capture.PNG

    Capture2.PNG

    wave train.PNG

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    Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL
    1 hour ago, bluearmy said:

    First seasonal Model out of the traps for September is cansips ......for those of a wintry disposition .......better not to look .... 

    This model was going for a moderate to strong La Nina, so perhaps this is the reason for such an output?

    Given Covid and the liklihood a cold winter will make it worse, then it is quids in we will end up with a cold one! ;)

    Edited by Radiating Dendrite
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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    2 hours ago, bluearmy said:

    First seasonal Model out of the traps for September is cansips ......for those of a wintry disposition .......better not to look .... 

    I won't!

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    Posted
  • Location: Netherlands
  • Location: Netherlands

    Hopefully we still see an EQBO.

    https://www.researchgate.net/publication/331874694_Influence_of_the_QBO_on_MJO_prediction_skill_in_the_subseasonal-to-seasonal_prediction_models

    Recent studies have shown that the Madden-Julian Oscillation (MJO) is significantly modulated by the stratospheric Quasi-Biennial Oscillation (QBO). In general, boreal winter MJO becomes more active during the easterly phase of the QBO (EQBO) than during the westerly phase (WQBO). Based on this finding, here we examine the possible impacts of the QBO on MJO prediction skill in the operational models that participated in the WCRP/WWRP subseasonal-to-seasonal (S2S) prediction project. All models show a higher MJO prediction skill during EQBO winters than during WQBO winters. For the bivariate anomaly correlation coefficient of 0.5, the MJO prediction skill during EQBO winters is enhanced by up to 10 days. This enhancement is insensitive to the initial MJO amplitude, indicating that the improved MJO prediction skill is not simply the result of a stronger MJO. Instead, a longer persistence of the MJO during EQBO winters likely induces a higher prediction skill by having a higher prediction limit.

    Combined with

    During La Niña years we also find the teleconnection from the MJO phases 6–8 makes the NAO– regime occur up to 2.5 times as often as the full climatology – this signal travels via the stratosphere, warming it and slowing the stratospheric polar vortex (Figure 4), with the total pathway taking around 20 days. There is a strong subseasonal link between the stratospheric polar vortex and the weather regimes throughout all winters [7], however, it is during La Niña years when there is the strongest subseasonal link between the MJO and the stratosphere.

    https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019GL084683

    & and a mentioned above not too strong La Nina.

    Edited by sebastiaan1973
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    Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

    Another update on the QBO for me now the latest 30hpa QBO figure has come in for August 2020 and for anyone who wants an EQBO for winter 2020/21 they better look away now

    qboindex.thumb.png.08989689679f8e847b76d7fc7b8a28c7.png

    July was at +0.34 so basically neutral QBO

    August has breached weak WQBO levels as it came in at +4.78

    Although having said that this isn't all doom and gloom for a colder winter based on the analysis I did for autumn QBO strength vs following winter CET values. Here is the analysis I did for the 4 winters that came in with a weak WQBO in the autumn preceding the winter.

                                                                                                                              4.89               4.15               4.21               4.42
                                                                                                                              1953 to 2019 1954 to 2020 1954 to 2020 1953 to 2020
    Weak W        Sep    Oct    Nov    AVERAGE Weak W    +2.00 to +5.99 CET    DEC Anom JAN Anom FEB Anom OVERALL Anom
    1995        + 6.98    + 3.43    - 0.77    + 3.21                        1995/96                  2.3              4.3             2.5
    1992        + 1.30    + 3.94    + 6.33    + 3.86                       1992/93                  3.6              5.9             4.6
    1973        + 5.51    + 5.20    + 4.92    + 5.21                       1973/74                  4.9              5.9             5.4
    1978        + 5.91    + 6.22    + 4.04    + 5.39                       1978/79                  3.9              -0.4            1.2
                                                                                                AVERAGE             3.68   -1.21 3.93 -0.22  3.43 -0.78  3.68          -0.74

    This analysis came out as my coldest option overall at -0.74 COLDER THAN AVERAGE ON AVERAGE

    I will be monitoring the 30 hpa QBO figures for October and November and if they can average out between +2.00 and +5.99 then we could be in for a chance at least but if it gets to moderate WQBO on average during the autumn then our cold chances reduce significantly

                                                                                                                        4.89                4.15              4.21               4.42
                                                                                                                        1953 to 2019 1954 to 2020 1954 to 2020 1953 to 2020
    Moderate W    Sep    Oct    Nov    AVERAGE Mod W +6.00 to +9.99 CET DEC Anom    JAN Anom     FEB Anom   OVERALL  Anom
    2004        + 7.29    + 8.00    + 4.35    + 6.55                        2004/05           5.4                 6.0                 4.3
    1963        + 3.52    + 7.54    + 8.87    + 6.64                        1963/64           2.6                 3.4                 4.5
    2019        + 8.25    + 7.27    + 5.07    + 6.86                        2019/20           5.8                 6.5                 6.7
    2002        + 8.90    + 7.66    + 4.46    + 7.01                        2002/03           5.7                 4.5                 3.9
    1982        + 4.21    + 8.27    + 9.51    + 7.33                        1982/83           4.4                 6.7                 1.7
    1961        + 6.02    + 7.59    + 8.74    + 7.45                        1961/62           2.2                 4.3                 4.4
    1987        + 5.88    + 9.35    + 9.23    + 8.15                        1987/88           5.6                 5.3                 4.9
    1955        + 8.16    + 9.02    + 7.63    + 8.27                        1955/56           5.4                 3.6                 -0.2
    1971        + 8.95    + 8.48    + 8.47    + 8.63                        1971/72           6.6                 3.9                 4.3
    1969        + 9.74    + 9.75    + 7.34    + 8.94                        1969/70           3.3                 3.7                 2.9
    1997        +11.64    + 9.91    + 5.74    + 9.10                       1997/98           5.8                 5.2                 7.3
    1999        +11.18    +10.62    + 6.01    + 9.27                      1999/00           5.0                 4.9                 6.3
    1957        + 8.36    +10.46    +10.11    + 9.64                      1957/58           4.5                 3.4                 4.7
    2010        + 6.58    +10.83    +12.16    + 9.86                      2010/11           -0.7                3.7                 6.4
                                                                                                AVERAGE       4.40    -0.49   4.65    +0.50  4.44    +0.23 4.50    +0.08

    This analysis came out overall at +0.08 MILDER THAN AVERAGE ON AVERAGE so very much close to average but milder probably more likely than not. However there are exception winters within this collection to the milder theme with 2010/11, 1969/70, December 1961, 1963/64, February 1955 and February 1983 as examples of colder winters on average or very cold months within a WQBO winter.

    The other thing which backs up the bad QBO news is the QBO chart below

    qbochart.thumb.jpg.9fb2d491c697d3f60627e1d9a53e1930.jpg

    This shows how we are now trending not much weaker than the 2019 WQBO a year ago now but we appear to be progressing quite quickly through the peak WQBO phase and are now heading into the area of the chart where soon we should be seeing the NASA Singapore site saying East, Descending phase

    The weak WQBO option could still be on however when taking look at the other developments in recent weeks

    First it is time to show the general QBO view from 10 hpa down to 300 hpa

    qbo10300general.thumb.jpg.ded8fe5ae51ac0214cab0177e6e1f219.jpg

    1 - On this general view it is clear to see the WQBO that appeared at 10 hpa has now gone but this still shows weak EQBO at best. It is maybe too early to see what route 10 hpa will go down next

    2 - The ever persistent WQBO has strengthened and the QBO figure for August 2020 did confirm this but rather than generally descending this area has just simply sat there at 30 hpa and expanded both up and down too. Not good news if you want an EQBO in time for winter

    3 - The only good news for the EQBO's chances to build and descend down from 10 hpa is that the easterly anomaly appears to have almost gone now and is only in the very lowest levels of the stratosphere now. You can see what effect it has had on the troposphere below with all those easterlies showing up there now

    Next is the overall general view but this time from 3 hpa down to 300 hpa

    qbo3300general.thumb.jpg.6b3fbd0d9cc6e9d43679c1e8512e3b33.jpg

    1 - This one shows up more of what has happened high up recently with new EQBO reforming between 3 hpa and 7 hpa with neutral to weak EQBO between 7 hpa and 15 hpa. It looks like we will have some easterlies at this height range for some time at least but will they descend down any further or just remain stuck up here

    2 and 3 - These areas are less detailed than in the previous chart but it does show up what has happened with the persistent westerlies and the easterly anomaly descending away.

    Now time to get into more detail with the detailed view of 10 hpa to 300 hpa

    qbo10300detail.thumb.jpg.f5ad9afe3a5c9bf1c5dd110d75b186b3.jpg

    1 - It is very clear to see on this chart how the WQBO at 10 hpa has run out of steam and has now switched back to an EQBO but a weak one at present. This should strengthen over the next few weeks but will it descend and push the 30 hpa WQBO away in time for winter, doubtful but if it does get its act together and does descend it could make the weak WQBO option for autumn more likely and so the -0.74 Colder signal would be favoured over the moderate WQBO +0.08 Milder signal.

    2 - This WQBO just refuses to do one and has just strengthened since it never got pushed away in the first place. This appears to be a watered down version of 2016 with the westerly region just narrower than it was back then and looking more likely to be temporary rather than a year long extension of WQBO

    3 - The easterly anomaly has little left to go now and should be gone in the next few weeks. This should help build a new EQBO higher up ready to descend later this year or early next year.

    Now time for the more detailed view of 3 hpa to 300 hpa

    qbo3300detail.thumb.jpg.f603a06eb9041558d8ae60f2138d0427.jpg

    1  - There are only 2 real areas of interest on here. The first is the peaking of the EQBO at 3 hpa but the only bad news from this is now they are starting to weaken again already. They need to drip feed their momentum down to below before they weaken too much or we will very likely end up with a continuation of the WQBO further down.

    2 - The good news for the EQBO is that the easterlies appear to be strengthening overall centred on 10 hpa in particular. The 0 to -5 m/s palest green is at all levels from 7 hpa to 15 hpa. The slightly darker pale green -5 to -10 m/s covers generally between 7 hpa and 12 hpa but if you look closely at 10 hpa on the far right of the chart you can just make out the next darkest green of -10 to -15 m/s starting to show up. That looks like the trend towards a new EQBO is continuing and if the trend continues we should see darker greens and maybe even some of the blues showing up in the next few weeks. Maybe too late for this winter but could be looking good for an EQBO winter in 2021/2022 and very likely a quite strong one by then too.

    Edited by SqueakheartLW
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    Posted
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow

    @sebastiaan1973 From August ENSO multimodel updates I reckon a week borderline moderate event is likely but I dont know weather QBO mess can be qualified as either westerly or easterly although higher up its looking like new westerly cycle will begin soon.Not easy to know what cards do we have coming in to cold season

     

    figure4.png

    ecmwfzm_u_f240 (1).png

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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
    11 minutes ago, jules216 said:

    @sebastiaan1973 From August ENSO multimodel updates I reckon a week borderline moderate event is likely but I dont know weather QBO mess can be qualified as either westerly or easterly although higher up its looking like new westerly cycle will begin soon.Not easy to know what cards do we have coming in to cold season

     

    figure4.png

    ecmwfzm_u_f240 (1).png

    How do the ENSO verification stats on those models stack up? The ECMWF doesn't appear to be interested in La Nina at all.

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  • Location: Netherlands
  • Location: Netherlands
    15 minutes ago, jules216 said:

    @sebastiaan1973 From August ENSO multimodel updates I reckon a week borderline moderate event is likely but I dont know weather QBO mess can be qualified as either westerly or easterly although higher up its looking like new westerly cycle will begin soon.Not easy to know what cards do we have coming in to cold season

     

     

     

    Thanks for your comment. Preferably we need an EQBO at 1-5 hPa in november. Altough it can go 'wrong' as in 2006. 

    Abstract

    The North Atlantic Oscillation (NAO), the regional manifestation of the Arctic Oscillation (AO), dominates winter climate variability in Europe and North America. Skilful seasonal forecasting of the winter NAO/AO has been demonstrated recently by dynamical prediction systems. However, the role of initial conditions in this predictability remains unknown. Using a latest generation seasonal forecasting system and reanalysis data, we show that the initial upper stratospheric zonal wind anomaly contributes to winter NAO/AO predictability through downward propagation of initial conditions. An initial polar westerly/easterly anomaly in the upper stratosphere propagates down to the troposphere in early winter, favoring a poleward/equatorward shift of the tropospheric mid-latitude jet. This tropospheric anomaly persists well into the late winter and induces the positive/negative phase of NAO/AO in the troposphere. Our results imply that good representation of stratospheric initial condition and stratosphere-troposphere coupling in models is important for winter climate prediction. https://iopscience.iop.org/article/10.1088/1748-9326/ab0385

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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    2 hours ago, Radiating Dendrite said:

    This model was going for a moderate to strong La Nina, so perhaps this is the reason for such an output?

    Given Covid and the liklihood a cold winter will make it worse, then it is quids in we will end up with a cold one! ;)

    I suppose La Nina and the bizarre QBO are causing long range models all kinds of headaches!

    Edited by Don
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  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow

    I have compiled my summer forecast based on criteria of emerging weak La Nina after week +ENSO and strong hurricane season forecast back in May. The general 500mb outcome against analogs proved very useful. One think I noted that low heights in analogs were much lower then actually materialized in June and August. There is clear  inability of lower heights to establish where we need them to = Mediterranean. The Scandi high pressure doesn't seem to have problem being as strong as advocated. From the years I looked that can be good analogs for winter there was a clear signal of low heights in Europe,almost a reverse of dreaded Euro high of recent winters. I can almost foresee where this winter can go wrong and that is the low heights getting stuck in wrong place around UK/IE somewhere and instead of promising Scandi block we will end up with Sceuro block. Not a showery  SW-W regime but more like promising synoptics in wrong place to advect cold from really cold source from E/NE. Most of the weak or moderate La Nina winters have a pronounced euro trough anomaly. Also Andrej @Recretos alluded to this exactly few days ago in the autumn forecast at SWE. Here is what he mentioned and I agree with this notion:

    "The quick look at the CFSv2 model trends reveals the exact same wave train, with the big temperature difference over Europe. That is simply because of the positioning of the European low-pressure area in this wave train. A simple movement of a few hundred to thousand kilometers north-south can create an entirely different temperature picture. That is why Europe is the biggest wildcard in this wave train pattern. North America is fairly fixed since it is heavily influenced by La Nina and the Pacific pattern."

     

    Already summer ended with much above average precipitation in Europe then recently as a direct feedback from La Nina, it is forecast to even strengthen during autumn,although seasonal wavelenghts are different in winter then in summer I believe the odds are much better for low pressure anomaly in Europe. The biggest question mark will be weather the wave train can cause it to be placed right for most of Europe to benefit from cold and that Scandi high doesn't become Sceuro high to cut us from source of cold air and bring only weak faux cold.

     

    leto 500mb.jpg

    compday.Dl5P9ifuoZ.gif

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  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    4 hours ago, jules216 said:

    @sebastiaan1973 From August ENSO multimodel updates I reckon a week borderline moderate event is likely but I dont know weather QBO mess can be qualified as either westerly or easterly although higher up its looking like new westerly cycle will begin soon.Not easy to know what cards do we have coming in to cold season

     

    Only that to get a cold season is increasingly difficult which is to be expected with climate change.  However, that doesn't make it any better!

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  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

    CANSIPS prognosis will be based on its forecast of a stronger nina. If that's wrong then its pressure forecasts will be too...

     

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  • Location: Rotherham
  • Weather Preferences: Snow, severe frost, freezing fog and summer sunshine
  • Location: Rotherham
    3 hours ago, CreweCold said:

    CANSIPS prognosis will be based on its forecast of a stronger nina. If that's wrong then its pressure forecasts will be too...

     

    A few months ago La Nina was forecast to be a weak affair (slight possibility of going moderate) as I recall. Has there been a change of thinking or is it just the CANSIPS model forecasting moderate-strong?

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  • Location: Carmarthenshire
  • Location: Carmarthenshire
    On 06/08/2020 at 19:25, SqueakheartLW said:

    Winter 1995/1996 is amongst the 4 winters featured as well as another cold classic 1978/1979. The two winters that could put the cold theory in jeopardy are 1992/1993 and 1973/1974 but overall when these winters are averaged out the anomalies come out colder than average for all 3 winter months. I imagine averaging out the winters helps to remove other factors at play during those winters and should result in the underlying QBO signal as a common factor with all of the winters. The data is below:

                                               Average CET 1953 to 2020           DEC - 4.89C    JAN - 4.15C    FEB - 4.21C     WINTER - 4.42C
                                           QBO Figures                         CET     1953 to 2019   1954 to 2020   1954 to 2020    1953 to 2020
    Autumn Weak WQBO   Sep     Oct      Nov    AV        Winter   DEC    Anom    JAN    Anom    FEB    Anom    OVERALL    Anom
                               1995   + 6.98 + 3.43 - 0.77 + 3.21  1995/96  2.30C -2.59C  4.30C +0.15C  2.50C  -1.71C   3.03C         -1.39C
                               1992   + 1.30 + 3.94 + 6.33+ 3.86  1992/93  3.60C -1.29C  5.90C +1.75C 4.60C   +0.39C  4.70C         +0.28C
                               1973   + 5.51 + 5.20 + 4.92+ 5.21  1973/74  4.90C +0.01C 5.90C +1.75C 5.40C   +1.19C  5.40C         +0.98C
                               1978   + 5.91 + 6.22 + 4.04+ 5.39  1978/79  3.90C -0.99C -0.40C  -4.55C 1.20C   -3.01C   1.57C         -2.85C
                                                                                  AVERAGE  3.68C -1.21C  3.93C  -0.22C 3.43C   -0.78C   3.68C         -0.74C

    I was interested in @SqueakheartLW's post about weak WQBO last month, here's the 500Mb anomaly for those years which suggests heights over Scandi which interestingly ties in with @jules216's thoughts above re ENSO.INVF9OZ_Ht.thumb.png.9b793490fdd0a2c5a03fce83ac97417e.png

    And taking the two years which didn't feature cold CET anomalies, 1973/4 and 1992/3 we seem to end up with @jules216's example of the Sceuro block.

    NrsibdYGP1.thumb.png.add5c4575163c48fa8d1051334996cb5.png

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  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
    6 hours ago, Catacol said:

    The sought after sweet spot I think from a statistical point is weak/moderate Niña and eQBO. There was a good chance of this developing....and then (as per the Masiello “lol”) we have had one half of that combination torn away. Call it bad luck... more likely call it climate change impacts. 
     

    Years of watching for cold winters has taught us all that we get mild and unremarkable about 4 winters out of 5, and that in the ones where cold develops it is usually only a shortish spell. I have reluctantly had to alter my own KPIs for success. Gone is the hope of a 63 or a 47 because I think these sorts of winters are now a part of history. Instead the short sharp cold shot is more realistic and we have seen these over the last 12 years. These will continue to happen, and perhaps climate change will make the freakish kind of Beast from the East vortex reversal more likely from time to time.
     

    For this reason smoothed average pressure anomaly charts over 1 or 3 months are about as much use as a chocolate teapot. We will still see snow from time to time when synoptics align to bring us cold air from north or east combined with a never ending supply of moisture from the west, but perhaps searching for a cold season across multiple weeks is now a hunt for fool’s gold. In that respect seeing the QBO once again pulled off course is unwelcome but not a deal breaker in the rather gloomy context of U.K. winters in a warming world. Just so long as it doesn’t end up being quite as bad as the winter we got after the last QBO disruption....

    Best and most realistic post I have seen for a long while on this forum. 

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