HIGHLIGHT:  The seasonal mean NINO3.4 anomaly was -1.0 C for NDJ2011/12, unchanged from OND. 

The CA method, acting on global NDJ2011/12 seasonal means as latest input, has all of its members on the cold side of neutral until early summer 2012.  La Nina conditions, but weaker than last year but in all 12 members, are thus expected by CA to stay in place into spring 2012. By JJA 2012 all members are in neutral territory. Some members crawl hesitantly into positive territory by summer 2012. No members go for an El Nino (>+0.5) later in 2012.

Weights have changed some in just one month. There are six years with high +ve weight!, but eight high -ve weight, an unusual ratio. The year 2008 (Jan 2011 or earlier check 2007) has carried a high +ve weight for 18 months in a row (this is why CA works as well as it does) but is slowly decreasing. OCN flavor is much reduced compared to a few years ago (only the period  >=2006 comes across with uniformly +ve weight, but 2002-2005 solidly negative). Expect bigger changes in one month because we will add at that time one year of data to the CA operator.

Table 1. Inner products (IP; scaled such that the sum of absolute values is 100; not shown) and weights (Wgt multiplied by 100.) of each of the years to construct an analogue to the sequence of 12 consecutive overlapping 3-month periods defined as the base (currently the 12 overlapping seasons string DJF2011 thru NDJ2011/12). Years in the table are labeled by the year of the middle month of the most recent predictor season. Weights for 1956 and 2010 are less (by 50%) because only half the members use these years ("early" members use 1956, "late" members 2010). Data currently thru Jan 2012.

Year

IP

Wgt

Year

IP

Wgt

Year

IP

Wgt

Year

IP

Wgt

Year

IP

Wgt

Year

IP

Weigt

1956

xx

 2

1966

xx

-7

1976

xx

 2

1986

xx

-12

1996

xx

10

2006

xx

11

1957

xx

-3

1967

xx

 3

1977

xx

 5

1987

xx

-13

1997

xx

 2

2007

xx

 5

1958

xx

-9

1968

xx

-11

1978

xx

 5

1988

xx

 -5

1998

xx

-2

2008

xx

15

1959

xx

-1

1969

xx

 4

1979

xx

-4

1989

xx

13

1999

xx

17

2009

xx

-2

1960

xx

-10

1970

xx

 6

1980

xx

 0

1990

xx

 0

2000

xx

 4

2010

xx

11

1961

xx

 3

1971

xx

 6

1981

xx

-2

1991

xx

-6

2001

xx

 2

2011

xx

NA

1962

xx

  4

1972

xx

 4

1982

xx

-1

1992

xx

-12

2002

xx

-4

xx

Xx

1963

xx

 8

1973

xx

-3

1983

xx

 0

1993

xx

-10

2003

xx

-11

xx

Xx

1964

xx

-3

1974

xx

 1

1984

xx

-16

1994

xx

 0

2004

xx

-1

xx

Xx

1965

xx

-7

1975

xx

 7

1985

xx

 0

1995

xx

-2

2005

xx

-4

xx

Xx

 

Weights are high +ve (>+0.10) for 2010, 2008, 2006,1999,1996,1989

Weights are high -ve (< - 0.10) for 2003,1993,1992,1987,1986,1984,1968,1960.

 

Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):

-1

-1

-0.95

-0.72

-0.51

-0.3

-0.11

0.01

0.03

0.02

0.02

0.02

0.09

0.2

0.28

0.23

0.21

0.18

0.24

0.25

0.25

NDJ

JFM12

MAM

MJJ

JAS

SON12

NDJ

JFM13

MAM

MJJ

JAS

One month ago:

-1.01

-1.01

-1.04

-1.01

-0.83

-0.65

-0.46

-0.27

-0.17

-0.15

-0.18

-0.15

-0.13

0.05

0.14

0.23

0.17

0.12

0.07

0.1

0.11

NDJ

JFM12

MAM

MJJ

JAS

SON

NDJ

JFM13

MAM

MJJ

Two months ago:

 

-0.89

-0.87

-0.89

-0.94

-0.92

-0.77

-0.6

-0.44

-0.29

-0.24

-0.26

-0.32

-0.31

-0.07

0.08

0.21

0.3

0.25

0.21

0.16

0.18

SON11

NDJ

JFM

MAM12

MJJ

JAS

SON

NDJ

JFM13

MAM

MJJ

Three months ago:

-0.76

-0.76

-0.75

-0.78

-0.79

-0.76

-0.63

-0.48

-0.35

-0.23

-0.22

-0.28

-0.36

-0.17

-0.08

0.07

0.22

0.3

0.26

0.24

0.23

SON11

NDJ

JFM12

MAM

MJJ

JAS

SON12

NDJ

JFM13

MAM

Four months ago:

-0.52

-0.51

-0.54

-0.56

-0.6

-0.62

-0.58

-0.48

-0.37

-0.25

-0.13

-0.1

-0.14

-0.02

0.04

0.14

0.22

0.3

0.28

0.19

0.11

JAS11

SON

NDJ

JFM12

MAM

MJJ

JAS

SON

NDJ

JFM13

MAM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Anomalies relative to 1981-2010 climo, as of the May 2011 release. Older forecasts (previous to May 2011 release) are relative to 71-2000