HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -0.6 C for FMA2012, down from NDJ (-1.0).
The CA method, acting on global FMA2012 seasonal means as latest input, but using a string of global SST going back one year, has all of its members going into neutral territory by MAM, i.e. ‘now’. Some members crawl hesitantly into positive territory by summer 2012. One member goes for an El Nino (>+0.5) late in 2012. One member is ‘hanging back’ and going into a 3rd year in-a-row La Nina, albeit very weak (-0.54).
Weights have changed only modestly from last month. Recall, we have increased the size of the covariance matrix by one from 54 to 55 a few months ago. This resulted in a re-arrangement because of co-linearity among the years (very few years are naturally orthogonal). Year 2000 carries a +0.19 weight, which is high in the business of a constructed analogue (a natural analogue would have weight 1.00; all other years 0.).
There are four (somewhat recent) years with high +ve weight!, and six (somewhat older) years with high -ve weight. OCN flavor is much reduced compared to a few years ago, but not completely gone.
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 MAM2011 thru FMA2012). Years in the table are labeled by the year of the middle month of the most recent predictor season. Weights for 1956 and 2011 are less (by 50%) because only half the members use these years ("early" members use 1956, "late" members 2011). Data currently thru Apr 2012.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
-1 |
1966 |
xx |
-12 |
1976 |
xx |
4 |
1986 |
xx |
-9 |
1996 |
xx |
-10 |
2006 |
xx |
-6 |
1957 |
xx |
8 |
1967 |
xx |
0 |
1977 |
xx |
4 |
1987 |
xx |
-10 |
1997 |
xx |
0 |
2007 |
xx |
14 |
1958 |
xx |
0 |
1968 |
xx |
-4 |
1978 |
xx |
9 |
1988 |
xx |
-7 |
1998 |
xx |
0 |
2008 |
xx |
9 |
1959 |
xx |
1 |
1969 |
xx |
-13 |
1979 |
xx |
5 |
1989 |
xx |
5 |
1999 |
xx |
0 |
2009 |
xx |
14 |
1960 |
xx |
-2 |
1970 |
xx |
1 |
1980 |
xx |
8 |
1990 |
xx |
-2 |
2000 |
xx |
19 |
2010 |
xx |
-7 |
1961 |
xx |
-6 |
1971 |
xx |
-9 |
1981 |
xx |
-1 |
1991 |
xx |
2 |
2001 |
xx |
7 |
2011 |
xx |
7 |
1962 |
xx |
8 |
1972 |
xx |
8 |
1982 |
xx |
-8 |
1992 |
xx |
2 |
2002 |
xx |
7 |
2012 |
xx |
NA |
1963 |
xx |
6 |
1973 |
xx |
-3 |
1983 |
xx
|
3 |
1993 |
xx |
5 |
2003 |
xx |
-3 |
xx |
Xx |
|
1964 |
xx |
2 |
1974 |
xx |
-4 |
1984 |
xx |
12 |
1994 |
xx |
-9 |
2004 |
xx |
0 |
xx |
Xx |
|
1965 |
xx |
2 |
1975 |
xx |
3 |
1985 |
xx |
-13 |
1995 |
xx |
-11 |
2005 |
xx |
-2 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2009,2007,2000,1984
Weights are high -ve (< - 0.10) for 1996,1995,1987,1985,1969,1966
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
-0.61 |
-0.51 |
-0.28 |
0.03 |
0.06 |
0.05 |
0 |
-0.01 |
-0.01 |
-0.01 |
-0.06 |
-0.02 |
-0.05 |
-0.07 |
-0.19 |
-0.19 |
-0.18 |
-0.18 |
-0.18 |
-0.17 |
-0.1 |
MAM2012 |
MJJ |
JAS |
SON |
NDJ |
JFM2013 |
MAM |
MJJ |
JAS |
SON |
One month ago
-0.82 |
-0.72 |
-0.49 |
-0.14 |
-0.02 |
0.01 |
-0.03 |
-0.1 |
-0.16 |
-0.19 |
-0.15 |
-0.11 |
-0.01 |
0.02 |
0.01 |
-0.05 |
-0.04 |
-0.01 |
-0.02 |
-0.02 |
-0.01 |
JFM12 |
MAM |
MJJ |
JAS |
SON |
NDJ |
JFM13 |
MAM |
MJJ |
JAS |
SON |
Two months ago:
-0.99 |
-0.93 |
-0.73 |
-0.36 |
-0.12 |
0.06 |
0.15 |
0.15 |
0.12 |
0.1 |
0.09 |
0.14 |
0.17 |
0.24 |
0.16 |
0.08 |
-0.01 |
0.01 |
0.01 |
0.01 |
0 |
JFM12 |
MAM |
MJJ |
JAS |
SON |
NDJ |
JFM13 |
MAM |
MJJ |
JAS |
Three months ago:
-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 |
Four months 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 |
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0.21 |
0.3 |
0.25 |
0.21 |
0.16 |
0.18 |
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JFM13 |
MAM |
MJJ |
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Anomalies relative to 1981-2010 climo, as of the May 2011 release. Older forecasts
(previous to May 2011 release) are relative to 71-2000