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OCTOBER PATTERN INDEX (OPI) MONITORING WINTER SEASON 2014-2015


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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

    16 day mean is stunning.

     

    Do we know the rolling AO value as well?

     

    tuDy7h0.gif

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    As ever, a great summary of how things stand from Ed and I think for the last 19, or pretty much 20 days now we have all been waiting for this point in the month and beyond. It's been rather 'fun' wat

    The discussion of the OPI index trend is understandably causing a lot of interest and (cautious) excitement amongst members after Riccardo's very interesting opening post that started this thread. The

    The monitoring page of the “October pattern index†(OPI) is presented. The OPI index  represents a analytic synthesis of the October hemispheric pattern at 500 hPa, and shows from  previous studi

    Posted Images

    Posted
  • Location: just behind Epsom Racecourse and the center of York
  • Location: just behind Epsom Racecourse and the center of York

    Great post Tamara almost a ramp !!!! Given the present ongoing eruption in iceland and the vast quantities of SO2 being pumped into the atmosphere and its effect on likely ozone production this can only bode well for any SSW events this winter IMO

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    Posted
  • Location: Lee, London. SE12, 41 mts. 134.5 ft asl.
  • Weather Preferences: Snowy, wintry weather
  • Location: Lee, London. SE12, 41 mts. 134.5 ft asl.

    Excellent post Tams and a well reasoned attempt to provide an insight into the complexities of interaction between teleconnecting elements and the meteorology behind what's driving the O.P.I. It's very compelling seeing all these composite analogue charts and previous years values but trying to understand the complex mechanisms that are producing these no doubt exciting findings, is another ballgame altogether.

    Perhaps Riccardo and his team could offer some insight into what they believe to be the mechanisms at work behind the O.P.I.

    This thread is making for an appetizing hors d'oeuvres as we head towards Winter and Tamara's post has added some meteorological meat to the very informative and well researched bones that Steve M and Phil, amongst others, have provided earlier in the thread.

    Regards,

    Tom,

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    CFS shows the NAO remaining negative or neutral (think I've spelt it right) for the foreseeable future

     

    naoindex.png

     

    Similar story for the AO

     

    aoindex.png

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    Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

    Increased meridionality of pressure patterns is observed during -QBO associated with solar minima. One might question that the current solar maxima might be an inhibiting spoiler in terms of favourable pattern feedback. Might we suppose that the low activity, in relative terms, we are experiencing within the current solar maxima, is enough to override/mitigate the inhibiting effects that higher solar flux phases have on ozone production and transport and associated overall stratosphere temperature reduction? Especially if the other factors driving the current OPI very negative continue to dominate as they suggest they might.

    :)

     

     

    A big post Tamara in content.  I think the maxima we are in is a minimal inhibitor to this singular winter due to it being such a low maxima and the bigger cycle overriding is of more general influence.  

    What are you measured views on the active volcano events of this year? 

     

    BFTP

    Edited by Paul
    Fixed the quote for you
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    Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

    I'm sure there was a paper on the 'pause' which looked at volcanoes from the point of view of "little and often" having just as important an effect on climate as a singular large eruption. The often is certainly applicable at present and some are not so little - those effects can only be enhanced with all the localised production of SO2 from the current Iceland eruption. Not sure how high the gasses from an effusive type event can reach but there is presently a large signature in the total column of the NH.

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    Excellent post Tams and a well reasoned attempt to provide an insight into the complexities of interaction between teleconnecting elements and the meteorology behind what's driving the O.P.I. It's very compelling seeing all these composite analogue charts and previous years values but trying to understand the complex mechanisms that are producing these no doubt exciting findings, is another ballgame altogether.

    Perhaps Riccardo and his team could offer some insight into what they believe to be the mechanisms at work behind the O.P.I.

    This thread is making for an appetizing hors d'oeuvres as we head towards Winter and Tamara's post has added some meteorological meat to the very informative and well researched bones that Steve M and Phil, amongst others, have provided earlier in the thread.

    Regards,

    Tom,

     

    Riccardo made a number of posts last year regarding OPI on this site - http://daltonsminima.altervista.org/author/riccardo/

    They're in Italian and are missing a few images, but can be muddled through with online translation and most images have been cached by Google (search using "site:" followed by url of page in question).

    His first OPI post outlines some of the theory behind it, and the reanalysis of 1984-5 for example gives some clues to how the calculation is made in practice.

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    Posted
  • Location: Lee, London. SE12, 41 mts. 134.5 ft asl.
  • Weather Preferences: Snowy, wintry weather
  • Location: Lee, London. SE12, 41 mts. 134.5 ft asl.

    Riccardo made a number of posts last year regarding OPI on this site - http://daltonsminima.altervista.org/author/riccardo/

    They're in Italian and are missing a few images, but can be muddled through with online translation and most images have been cached by Google (search using "site:" followed by url of page in question).

    His first OPI post outlines some of the theory behind it, and the reanalysis of 1984-5 for example gives some clues to how the calculation is made in practice.

    Thanks Interitus.

    Actually my mother was Italian but I'm ashamed to say, "Che il mio Italiano non e perfetto!" :(

    I've had a look at the forum that Riccardo posts on and understand some of it but not all. Going to get my younger sister to have a look, she's the real Italian speaker in the family!

    Ciao,

    Tom.

    Edited by Kentish Blues Man
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    Posted
  • Location: New Ash green 150M / 500 FT
  • Location: New Ash green 150M / 500 FT

    Hum.....

     

    that's a rather large correction..... could be an outlier..... (12z GFS)!!!!

     

    http://app.til.it/opi/

     

    more data required.  Maybe some human intervention....

     

    rolling average 1.87-

     

    S

    Edited by Steve Murr
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    Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

    Riccardo made a number of posts last year regarding OPI on this site - http://daltonsminima.altervista.org/author/riccardo/

    They're in Italian and are missing a few images, but can be muddled through with online translation and most images have been cached by Google (search using "site:" followed by url of page in question).

    His first OPI post outlines some of the theory behind it, and the reanalysis of 1984-5 for example gives some clues to how the calculation is made in practice.

     

    I had only followed the OPI discussions on the American forum - quite surprised by how wrong the European forecast was. There is a danger in favouring climatology at the present time - the weather patterns are not doing climatology of late!

     

    Whether you think the displaced jet stream and HLB are caused by climate change, ice loss or solar inactivity is immaterial; the end result is a greater degree of unpredictability. We'll just need to hope that it is our turn for a displaced lobe of the polar vortex. :cold:

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    Hum.....

     

    that's a rather large correction..... could be an outlier..... (12z GFS)!!!!

     

    http://app.til.it/opi/

     

    more data required.  Maybe some human intervention....

     

    rolling average 1.87-

     

    S

     

     

    I wonder where it comes from this surge since the last GFS 12Z, there is absolutely no change on the side of the Arctic compared to the 6Z GFS, at least up to 240h

     

     

    Rhavn1801.gif

    Edited by neige57
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    Posted
  • Location: New Ash green 150M / 500 FT
  • Location: New Ash green 150M / 500 FT

    As said could be modified.....

     

    S

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    Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

    I realise it is the amalgam of the ten days but at plus 240 there are marked difference in heights to our north between 06Z and 12Z.

     

    gfsnh-2014101006-12-240_dwt7.pnggfsnh-12-240_saj4.png

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    Posted
  • Location: west yorkshire
  • Weather Preferences: extreme weather
  • Location: west yorkshire

    Looking through the gefs members seems unlikely a strong vortex will build in the next 2 weeks. Building blocks seem to so far be falling into place nicely.

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    Looking through the gefs members seems unlikely a strong vortex will build in the next 2 weeks. Building blocks seem to so far be falling into place nicely

    what does this indicate terrier! thanks is it on cue for a cold winter

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    Posted
  • Location: New Ash green 150M / 500 FT
  • Location: New Ash green 150M / 500 FT

    Hum.....

     

    that's a rather large correction..... could be an outlier..... (12z GFS)!!!!

     

    http://app.til.it/opi/

     

    more data required.  Maybe some human intervention....

     

    rolling average 1.87-

     

    S

     

    With corrections such as the one seen today, it does just cast a shadow over the integrity of the way the measure is worked out-

    Assuming the GFS has minimal corrections at Day 5

     

    then we see the following swing from 06z to 12z.

     

    Day 10 rolling + 10 day forecast ( 06z ) was -3.91,  If the rolling average was -1.87 at day 10 then to get to -3.91 at day 10 the forecast had to be -5.95

     

    Now on 12z

    Day 10 rolling + 10 Day forecast (12z) is -1.13 . so going on the same rolling average of -1.87 the 10 day forecast would have to be -0.39 across the 10 days.

     

    All things being equal, there seems to be to much swing in the 5-10 day range to go from one extreme to another.

     

    In terms of the calculation either the algorithm was wrong or some sort of human modification has taken place....

     

    ideally we would need Riccardo to comment on what the issue is. However its disappointing to see a swing after commenting on the consistency of the index over the last 24 hours going from 3.54 to 3.85 to 3.91

     

    regards

    Steve

    Edited by Steve Murr
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    Posted
  • Location: Hadleigh, Suffolk
  • Weather Preferences: An Alpine climate - snowy winters and sunny summers
  • Location: Hadleigh, Suffolk

    I wonder where it comes from this surge since the last GFS 12Z, there is absolutely no change on the side of the Arctic compared to the 6Z GFS, at least up to 240h

     

    Well knock me down with a feather!! I quite agree with neige57's comment.

    EDIT: And Steve's excellent comments above.

     

    If you look at the GFS 12z Nth Hemisphere chart all the way out at 26th Oct there is still a large high pressure dominating the Pole. So a puzzle why the big drop in the Index between the 06z and 12z today. I guess we need to study the link that Interitus posted earlier and better understand the way the OPI is calculated. And if Steve's earlier comment is right about human intervention "modifying" the output, why?? 

     

    Today's GFS 12z for 26th Oct: post-20040-0-85794600-1412969243_thumb.p

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    Posted
  • Location: Sowerby Bridge, West Yorkshire
  • Weather Preferences: Click on my name - sorry, it was too long to fit here......
  • Location: Sowerby Bridge, West Yorkshire

    Are we sure that it's calculated on a rolling average?

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    Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

    Presumably larger swings are always more likely earlier on in the month whilst we are still including a forecast period as it were, but this is a huge swing that makes little sense to me.

    It will be interesting to see what the next run bring although did I read the 18z is not included?

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    Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

    Well knock me down with a feather!! I quite agree with neige57's comment.

    EDIT: And Steve's excellent comments above.

    If you look at the GFS 12z Nth Hemisphere chart all the way out at 26th Oct there is still a large high pressure dominating the Pole. So a puzzle why the big drop in the Index between the 06z and 12z today. attachicon.gifGFS 12z npsh500 for 26Oct2014.png

    This is a pertinent point. For such a swing, you really would expect to see a very different NH profile than this Edited by s4lancia
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    Posted
  • Location: st albans
  • Location: st albans

    Whilst one would normally need ones bumps feeling to predicate something on gfs low res, the fact that the OPI is a rolling number updated every 6 hours should flatten out the effect of any strange runs. something does seem very odd about the sudden change seen today. As the 18z isn't used, we will have to wait for later tomorrow morning to see the update based on the 00z run.

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    Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

    Following the ens the actual AO was always trending back up after this week,but still on the mean negative side.Although the OPI is based on different data this must affect it somewhat although that is quite a jump I agree.

    I suppose we are still going into FI territory and tonights gefs have quite a wide spread on the AO graph so swings on this are still likely until we have more actual days recorded later in the month.

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