HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -1.58 for SON2010, a slight decrease from ASO (-1.44), but significant in the sense that La Nina may now be strong (more than 1.5).
The CA method, acting on global SON2010 seasonal means as latest input forecasts the 3 mo running mean anomaly for Nino34, has 100% of its members in strong La Nina territory for the rest of the year and hovering near -2C at the peak in DJF, making it a strong La Nina. La Nina condition are expected by CA thru AMJ2011, followed by weak +ve anomalies slightly above +0.5 (in the fall of 2011), the El Nino criterion.
Weights have developed some from last month. There are nine years with high +ve weight!, and four high -ve weight. OCN flavor is present: many +ve weights in recent years, but high +ve weights for 1969, 1973 also point to interdecadal variation. The high –ve weights are 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 OND2009 thru SON2010). Years in the table are labeled by the year of the middle month of the most recent predictor season. Weights for 1956 and 2009 are less (by 50%) because only half the members use these years ("early" members use 1956, "late" members 2009). Data currently thru Nov 2010.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
2 |
1966 |
xx |
2 |
1976 |
xx |
-5 |
1986 |
xx |
-8 |
1996 |
xx |
8 |
2006 |
xx |
3 |
1957 |
xx |
-4 |
1967 |
xx |
-6 |
1977 |
xx |
-1 |
1987 |
xx |
3 |
1997 |
xx |
-3 |
2007 |
xx |
19 |
1958 |
xx |
-6 |
1968 |
xx |
-4 |
1978 |
xx |
1 |
1988 |
xx |
10 |
1998 |
xx |
11 |
2008 |
xx |
22 |
1959 |
xx |
-5 |
1969 |
xx |
12 |
1979 |
xx |
1 |
1989 |
xx |
5 |
1999 |
xx |
2 |
2009 |
xx |
0 |
1960 |
xx |
-4 |
1970 |
xx |
9 |
1980 |
xx |
5 |
1990 |
xx |
4 |
2000 |
xx |
-5 |
2010 |
xx |
NA |
1961 |
xx |
-1 |
1971 |
xx |
-1 |
1981 |
xx |
3 |
1991 |
xx |
-2 |
2001 |
xx |
2 |
xx |
Xx |
|
1962 |
xx |
5 |
1972 |
xx |
-2 |
1982 |
xx |
-16 |
1992 |
xx |
-4 |
2002 |
xx |
3 |
xx |
Xx |
|
1963 |
xx |
-1 |
1973 |
xx |
11 |
1983 |
xx
|
-3 |
1993 |
xx |
-3 |
2003 |
xx |
7 |
xx |
Xx |
|
1964 |
xx |
0 |
1974 |
xx |
-3 |
1984 |
xx |
-20 |
1994 |
xx |
-11 |
2004 |
xx |
-1 |
xx |
Xx |
|
1965 |
xx |
-14 |
1975 |
xx |
9 |
1985 |
xx |
2 |
1995 |
xx |
11 |
2005 |
xx |
5 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2008, 2007,2005,1998,1995,1988,1973,1969. Weights are high -ve (< - 0.10) for 1994,1984,1982,1965.
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
-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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One month 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 |
Two months ago
-1.17 |
-1.25 |
-1.49 |
-1.88 |
-2.03 |
-1.98 |
-1.71 |
-1.19 |
-0.7 |
-0.3 |
-0.03 |
0.14 |
0.27 |
0.38 |
0.51 |
0.59 |
0.6 |
0.54 |
0.43 |
0.37 |
0.38 |
JAS |
SON |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
JFM12 |
MAM |
Three months ago:
-0.83 |
-0.89 |
-1.14 |
-1.53 |
-1.79 |
-1.96 |
-1.94 |
-1.7 |
-1.22 |
-0.76 |
-0.38 |
-0.14 |
0.01 |
0.14 |
0.24 |
0.35 |
0.39 |
0.37 |
0.3 |
0.2 |
0.18 |
JAS |
SON |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
JFM12 |
Four months ago:
|
-0.49 |
-0.52 |
-0.71 |
-1.08 |
-1.33 |
-1.63 |
-1.83 |
-1.83 |
-1.63 |
-1.19 |
-0.75 |
-0.37 |
-0.15 |
-0.01 |
0.13 |
0.24 |
0.34 |
0.36 |
0.3 |
0.18 |
0.07 |
|
MJJ |
JAS |
SON |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON |
NDJ |
JFM12 |
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Anomalies relative to
1971-2000 climo.