HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -1.25 for DJF2010/11, down from NDJ (-1.50). La Nina has been “peaking” for several months but appears to weaken, not unusual for the season.
The CA method, acting on global DJF2011 seasonal means as latest input, has 100% of its members in La Nina territory thru AMJ. La Nina conditions, but weaker and some members not making -.5, are expected by CA for the indefinite future. This is a change from 3 months ago when a change into positive territory was predicted for summer 2011.
Weights have changed because a) the matrix size has increased by one, from 53 to 54, and this resets the weights given co-linearity among years, and b) weights (if conserved) have moved into the next year. There are eight years with high +ve weight!, and seven high -ve weight. OCN flavor is present: many +ve weights in recent years, but continuing high +ve weights for around 1970-74 also point to interdecadal variation. Still, the high –ve weights are generally older than the high +ve weights.
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 JFM2010 thru DJF2010/11). 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 Feb 2011. Note changes because one full year of data is added.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
4 |
1966 |
xx |
-11 |
1976 |
xx |
9 |
1986 |
xx |
-10 |
1996 |
xx |
8 |
2006 |
xx |
-2 |
1957 |
xx |
-9 |
1967 |
xx |
1 |
1977 |
xx |
-15 |
1987 |
xx |
-17 |
1997 |
xx |
13 |
2007 |
xx |
8 |
1958 |
xx |
-3 |
1968 |
xx |
-8 |
1978 |
xx |
6 |
1988 |
xx |
-1 |
1998 |
xx |
0 |
2008 |
xx |
15 |
1959 |
xx |
-3 |
1969 |
xx |
1 |
1979 |
xx |
-1 |
1989 |
xx |
11 |
1999 |
xx |
7 |
2009 |
xx |
7 |
1960 |
xx |
-6 |
1970 |
xx |
11 |
1980 |
xx |
-2 |
1990 |
xx |
-4 |
2000 |
xx |
10 |
2010 |
xx |
8 |
1961 |
xx |
-4 |
1971 |
xx |
15 |
1981 |
xx |
5 |
1991 |
xx |
6 |
2001 |
xx |
-13 |
2011 |
xx |
NA |
1962 |
xx |
3 |
1972 |
xx |
-6 |
1982 |
xx |
3 |
1992 |
xx |
-4 |
2002 |
xx |
10 |
xx |
Xx |
|
1963 |
xx |
4 |
1973 |
xx |
0 |
1983 |
xx
|
-5 |
1993 |
xx |
-9 |
2003 |
xx |
-2 |
xx |
Xx |
|
1964 |
xx |
0 |
1974 |
xx |
20 |
1984 |
xx |
-5 |
1994 |
xx |
-7 |
2004 |
xx |
2 |
xx |
Xx |
|
1965 |
xx |
-10 |
1975 |
xx |
-4 |
1985 |
xx |
-13 |
1995 |
xx |
-8 |
2005 |
xx |
3 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2008, 2002, 2000,1997,1989,1974,1971,1970. Weights are high -ve (< - 0.10) for 2001,1987,1986,1985,1977,1966,1965.
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
-1.46 |
-1.49 |
-1.33 |
-0.99 |
-0.78 |
-0.69 |
-0.67 |
-0.65 |
-0.66 |
-0.71 |
-0.79 |
-0.77 |
-0.67 |
-0.47 |
-0.27 |
-0.05 |
0.03 |
0.09 |
0.08 |
0.15 |
0.2 |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
JFM12 |
MAM |
MJJ |
JAS12 |
One month ago:
-1.54 |
-1.62 |
-1.66 |
-1.39 |
-1.07 |
-0.83 |
-0.67 |
-0.6 |
-0.57 |
-0.59 |
-0.62 |
-0.69 |
-0.68 |
-0.5 |
-0.36 |
-0.21 |
-0.02 |
0.08 |
0.17 |
0.2 |
0.27 |
NDJ |
JFM |
MAM11 |
MJJ |
JAS |
SON |
NDJ |
JFM12 |
MAM |
MJJ |
JAS |
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Two months ago: -1.54 |
-1.67 |
-1.86 |
-1.88 |
-1.47 |
-1.07 |
-0.78 |
-0.54 |
-0.38 |
-0.24 |
-0.19 |
-0.14 |
-0.16 |
-0.07 |
-0.07 |
-0.06 |
-0.02 |
0.11 |
0.23 |
0.33 |
0.36 |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
JFM12 |
MAM |
MJJ |
Three months ago:
-1.58 |
-1.67 |
-1.91 |
-2.12 |
-1.91 |
-1.42 |
-0.94 |
-0.55 |
-0.23 |
0 |
0.2 |
0.32 |
0.45 |
0.56 |
0.61 |
0.56 |
0.5 |
0.41 |
0.39 |
0.38 |
0.38 |
SON10 |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
DJF12 |
FMA |
AMJ12 |
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Four months ago
-1.44 |
-1.51 |
-1.75 |
-2.09 |
-2.06 |
-1.79 |
-1.26 |
-0.75 |
-0.34 |
-0.04 |
0.17 |
0.34 |
0.48 |
0.62 |
0.7 |
0.73 |
0.67 |
0.56 |
0.45 |
0.43 |
0.44 |
SON |
NDJ |
JFM11 |
MAM |
MJJ |
JAS11 |
SON |
NDJ |
JFM12 |
MAM |
Anomalies relative to
1971-2000 climo.