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Anologues!


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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

    I have opened this thread in order to see how much use anologues actually are (i.e. how far can we accurately predict with them), while this thread will only be related to the indicee values, because anologues are subjective (i.e. you can take La Nina to mean higher pressure in one are, but somebody may take it to mean lower pressure in that area...).

    I will do this by posting both the duo-monthly anologues, and the predicted indicee values for the October to March period, at the end of the month, allowing a 0.3 margin of error, i will then deem the forecast to be a success or failure and post the next set of anologues and predicted indicees, however at the end of that month, i will rate both, because it could be that several anologues were present in both sets of data, over a longer time period, this would allow me to find a persistant anologue which would allow me to better my future forecasts for the coming period.

    Here is the first set of data...

    Oct to March

    MEI

    Sep

    1999

    -1.1 (Correct)

    -1.2

    -1.4

    -1.3

    -1.3

    -1.1

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    Sep

    2005

    1996

    -2.1 (Correct)

    -2.1

    -1.5

    -0.6

    -0.6

    0.1

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    AO

    Sep

    2003

    2002

    2000

    1997

    1985

    1980

    1973

    1970

    1967

    1962

    1954

    0 (Wrong)

    -0.6

    -1.1

    -1.4

    -1.3

    0.1

    http://www.cpc.noaa.gov/products/precip/CW...ent.ascii.table

    As you can see from this, all three forecasts were within 0.4 of the forecast value, however as my margin of error is 0.3, i did not predict the October AO value well enougth, thus on a A-F scale, i would rate this forecast a C.

    I now have the updated anologues, with associated indicee values and also the median CET value for the anologues which are present in more than one indicee...

    Oct to March

    MEI

    Sep

    1999

    -1.1 (Correct)

    -1.2

    -1.4

    -1.3

    -1.3

    -1.1

    Oct

    1999

    1970

    1964

    1954

    -1

    -1.1

    -0.9

    -0.7

    -0.9

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    Sep

    2005

    1996

    -2.1 (Correct)

    -2.1

    -1.5

    -0.6

    -0.6

    0.1

    Oct

    2005

    -2.5

    -2.1

    -1.7

    -1.1

    -0.1

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    AO

    Sep

    2003

    2002

    2000

    1997

    1985

    1980

    1973

    1970

    1967

    1962

    1954

    0 (Wrong)

    -0.6

    -1.1

    -1.4

    -1.3

    0.1

    Oct

    2000

    1975

    1973

    1970

    1969

    1955

    1954

    -0.3

    -0.4

    -0.9

    0.2

    -0.5

    Temperature Outcome

    1954

    1970

    November: 7.4C, 0.5C above average

    December: 5.6C, 0.5C above average

    January: 3.6C, 0.6C below average

    February: 2.9C, 1.3C below average

    March: 4.1C, 2.2C below average

    Please feel free to give your own opinion on the use of anologues.

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    Posted
  • Location: Coventry,Warwickshire
  • Location: Coventry,Warwickshire

    I had 1970 down as an analgue based on the time of year and direction of change of the QBO and El Nino indices. As to how usefull they are then I am not so sure. The stratosphere is a lot colder, the ice melt during the summer was a lot more and these things are likely to throw the patterns in a different direction.

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    • 1 month later...
    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

    Oct to March

    MEI

    Sep

    1999

    -1.1 (Correct)

    -1.2 (Correct)

    -1.4

    -1.3

    -1.3

    -1.1

    Oct

    1999

    1970

    1964

    1954

    -1 (Correct)

    -1.1

    -0.9

    -0.7

    -0.9

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    Sep

    2005

    1996

    -2.1 (Correct)

    -2.1 (Correct)

    -1.5

    -0.6

    -0.6

    0.1

    Oct

    2005

    -2.5 (Correct)

    -2.1

    -1.7

    -1.1

    -0.1

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    AO

    Sep

    2003

    2002

    2000

    1997

    1985

    1980

    1973

    1970

    1967

    1962

    1954

    0 (Wrong)

    -0.6 (Correct)

    -1.1

    -1.4

    -1.3

    0.1

    Oct

    2000

    1975

    1973

    1970

    1969

    1955

    1954

    -0.3 (Correct)

    -0.4

    -0.9

    0.2

    -0.5

    Temperature Outcome

    1954

    1970

    November: 7.4C, 0.5C above average (Correct, actual was 7.3C)

    December: 5.6C, 0.5C above average

    January: 3.6C, 0.6C below average

    February: 2.9C, 1.3C below average

    March: 4.1C, 2.2C below average

    Please feel free to give your own opinion on the use of anologues.

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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

    As you can see above, the use of anologues at the one and two month timeframe was succesful, as such, we could use Novembers data to get a clear picture of the indices for the coming winter.

    Here is the November data...

    MEI

    Sep

    1999

    Oct to March

    -1.1 (Correct)

    -1.2 (Correct)

    -1.4

    -1.3

    -1.3

    -1.1

    Oct

    1999

    1970

    1964

    1954

    Nov to March

    -1 (Correct)

    -1.1

    -0.9

    -0.7

    -0.9

    Nov

    1999

    1974

    1964

    Dec to March

    -1.1

    -0.8

    -0.6

    -0.5

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    Sep

    2005

    1996

    Oct to March

    -2.1 (Correct)

    -2.1 (Correct)

    -1.5

    -0.6

    -0.6

    0.1

    Oct

    2005

    Nov to March

    -2.5 (Correct)

    -2.1

    -1.7

    -1.1

    -0.1

    Nov

    N/A (Trend)

    Dec to March

    -2.1

    2005

    -1.4

    -0.8

    +0.2

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    AO

    Sep

    2003

    2002

    2000

    1997

    1985

    1980

    1973

    1970

    1967

    1962

    1954

    Oct to March

    0 (Wrong)

    -0.6

    -1.1

    -1.4

    -1.3

    0.1

    Oct

    2000

    1975

    1973

    1970

    1969

    1955

    1954

    Nov to March

    -0.3 (Correct)

    -0.4

    -0.9

    0.2

    -0.5

    Nov

    1995

    1964

    1954

    Dec to March

    -1.1

    -1.2

    -1.4

    -1.4

    http://www.cpc.noaa.gov/products/precip/CW...ent.ascii.table

    Temperature Outcome

    1964

    December: 3.5C, 1.6C below average

    January: 3.2C, 1C below average

    February: 3C, 1.2C below average

    March: 5.1C, 1.2C below average

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    • 2 months later...
    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
    MEI

    Nov

    1999

    1974

    1964

    Dec to March

    -1.1 (Correct)

    -0.8 (Correct)

    -0.6

    -0.5

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    Nov

    N/A (Trend)

    Dec to March

    -2.1 (Wrong)

    2005

    -1.4 (Wrong)

    -0.8

    +0.2

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    AO

    Nov

    1995

    1964

    1954

    Dec to March

    -1.1 (Wrong)

    -1.2 (Wrong)

    -1.4

    -1.4

    http://www.cpc.noaa.gov/products/precip/CW...ent.ascii.table

    Temperature Outcome

    1964

    December: 3.5C, 1.6C below average (Wrong)

    January: 3.2C, 1C below average (Wrong)

    February: 3C, 1.2C below average

    March: 5.1C, 1.2C below average

    The main points of analysis were that the MEI values were once again predicted within an acceptable margin of error, while the QBO (easterly trades) collapsed much quicker than expected, and the AO values were just wrong.

    This in turn led to my temperature profile anologue (1964), also being wrong and as a result of the QBO weakening quicker than forecast, i would surmise that this has allowed the Polar Vortex to be much stronger than forecast, though it should be noted that with December and Janury averaging an AO value of +0.8, this would actually be considered near neutral.

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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

    Looking ahead to summer now, i am now going to include the forecast data to August.

    MEI

    2000

    1999

    1989

    1971

    1957

    1955

    1951

    1950

    March to August

    -0.7

    -0.7

    -0.4

    -0.8

    -0.6

    -0.6

    http://www.cdc.noaa.gov/Correlation/mei.data

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    • 2 weeks later...
    Posted
  • Location: Steeton, W Yorks, 270m ASL
  • Location: Steeton, W Yorks, 270m ASL
    The main points of analysis were that the MEI values were once again predicted within an acceptable margin of error, while the QBO (easterly trades) collapsed much quicker than expected, and the AO values were just wrong.

    This in turn led to my temperature profile anologue (1964), also being wrong and as a result of the QBO weakening quicker than forecast, i would surmise that this has allowed the Polar Vortex to be much stronger than forecast, though it should be noted that with December and Janury averaging an AO value of +0.8, this would actually be considered near neutral.

    So are we concluding that the method is flawed yet? How might it be improved?

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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
    So are we concluding that the method is flawed yet? How might it be improved?

    I will update later on today hopefully, if not soon...

    However, from this the conclusions thus far are that some teleconnections have a much better anologue response than others (MEI as opposed to the AO for example), however given that we saw a record low QBO value, there are no comperable anologues for that which is why the anologues could not forecast that.

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    • 2 months later...
    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

    QBO

    2006

    2000

    1997

    1990

    1988

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    MEI

    1976

    1956

    1950

    June to November

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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

    Sorry, i did'nt have time to finish, after applying a linier ajjustment, here are the results.

    QBO

    2006

    1997

    1990

    1988

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    MEI

    1976

    1956

    1950

    http://www.cdc.noaa.gov/Correlation/mei.data

    June to November

    QBO

    0.6

    0.8

    0.7

    0.7

    0.6

    0.6

    MEI

    -0.4

    -0.2

    0

    0.1

    0

    -0.2

    Temperature profile

    June: 15.1C, 1C above average

    July: 17.2C, 0.7C above average

    August: 16.2C, average

    September: 14.9C, 1.2C above average

    October: 11.2C, 0.8C above average

    November: 6.8C, 0.1C below average

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    • 1 month later...
    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

    Here are the anologues which matched the April-May period as duo-monthly anologues...

    MEI

    1999

    1989

    1976

    1967

    1963

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    2006

    1997

    1990

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    After applying a linier ajustment, here are the expected monthly readings for the QBO and MEI...

    MEI

    0.1

    0.1

    0.2

    0.2

    0.2

    0.1

    QBO

    1.6

    1.8

    1.6

    1.5

    1.3

    1.1

    Based on the data above, here would be my forecast for the next six months...

    Forecast...

    June: Above average temperature, Above average rainfall

    July: Above average temperature, Average rainfall

    August: Below average temperature, Above average rainfall

    September: Below average temperature, Average rainfall

    October: Below average temperature, Average rainfall

    November: Below average temperature, Above average rainfall

    As you can see, the QBO anologues have not changed at all, and it is interesting to see 1976 and 2006 both as anologues for the current tri-monthly period.

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    • 1 month later...
    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

    Here are the anologues which matched the May-June period as duo-monthly anologues...

    MEI

    1996

    1985

    1976

    1963

    1961

    1951

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    2006

    2004

    2002

    1999

    1997

    1995

    1990

    1985

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    After applying a linier ajustment, here are the expected monthly readings for the QBO and MEI...

    MEI

    +0.3

    +0.4

    +0.3

    +0.4

    +0.5

    +0.3

    QBO

    Will complete at later date..

    Interestingly, it looks like we will border on a weak El Nino for the next six months, i believe the chance of a weak El Nino being declared is now 40%, with neutral conditions favoured.

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    from IRI 16 July

    It indicates a 75% probability for ENSO-neutral conditions in the coming season.

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    Posted
  • Location: W. Northants
  • Location: W. Northants

    I still think we'll see a neutral autumn and early wimter and then probably trending towards weak or moderate La Nina late winter and spring 2009.

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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
    When you say "anologue" do you actually mean "analogue"?

    Yes!

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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

    Here are the anologues which matched the May-June period as duo-monthly anologues...

    MEI

    1996

    1985

    1976

    1963

    1961

    1951

    http://www.cdc.noaa.gov/Correlation/mei.data

    QBO

    2006

    2004

    1999

    1997

    1990

    http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

    After applying a linier ajustment, here are the expected monthly readings for the QBO and MEI...

    MEI

    +0.3

    +0.4

    +0.3

    +0.4

    +0.5

    +0.3

    QBO

    +1.5

    +1.4

    +1.3

    +1.1

    +0.7

    +0.2

    Interestingly, it looks like we will border on a weak El Nino for the next six months, i believe the chance of a weak El Nino being declared is now 40%, with neutral conditions favoured.

    August: Above average rainfall, close to average temperature

    September: Above average rainfall, close to average temperature

    October: Close to average rainfall, below average temperature

    November: Below average rainfall, close to average temperature

    December: Below average rainfall, close to average temperature

    January: Above average rainfall, close to average temperature

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