HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -1.44 for ASO2010, a considerable decrease from JAS(-1.17).
The CA method, acting on global ASO2010 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, making it a strong La Nina surpassed by very few. The ensemble mean peaks at -2.09 which would be a tie for the record since 1950. Empirical tools do not predict a record value too often.
Weights have developed some from last month. There are nine years with high –ve weight!, and four high +ve weight. The negative (positive) weight assigned to 1997 (1998) is noteworthy. OCN flavor is present: many +ve weights in recent years, but high +ve weights for 1969, 1970, 1973 points to interdecadal variation.
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 SON2009 thru ASO2010). 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 Oct 2010.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
3 |
1966 |
xx |
1 |
1976 |
xx |
-9 |
1986 |
xx |
-6 |
1996 |
xx |
5 |
2006 |
xx |
2 |
1957 |
xx |
-4 |
1967 |
xx |
-5 |
1977 |
xx |
-3 |
1987 |
xx |
3 |
1997 |
xx |
-9 |
2007 |
xx |
15 |
1958 |
xx |
-7 |
1968 |
xx |
-4 |
1978 |
xx |
0 |
1988 |
xx |
11 |
1998 |
xx |
11 |
2008 |
xx |
19 |
1959 |
xx |
-7 |
1969 |
xx |
17 |
1979 |
xx |
1 |
1989 |
xx |
12 |
1999 |
xx |
-2 |
2009 |
xx |
-1 |
1960 |
xx |
-6 |
1970 |
xx |
10 |
1980 |
xx |
2 |
1990 |
xx |
3 |
2000 |
xx |
3 |
2010 |
xx |
NA |
1961 |
xx |
-3 |
1971 |
xx |
-2 |
1981 |
xx |
5 |
1991 |
xx |
4 |
2001 |
xx |
0 |
xx |
Xx |
|
1962 |
xx |
7 |
1972 |
xx |
-1 |
1982 |
xx |
-15 |
1992 |
xx |
4 |
2002 |
xx |
9 |
xx |
Xx |
|
1963 |
xx |
-2 |
1973 |
xx |
10 |
1983 |
xx
|
-1 |
1993 |
xx |
0 |
2003 |
xx |
3 |
xx |
Xx |
|
1964 |
xx |
4 |
1974 |
xx |
-1 |
1984 |
xx |
-21 |
1994 |
xx |
-14 |
2004 |
xx |
1 |
xx |
Xx |
|
1965 |
xx |
-17 |
1975 |
xx |
7 |
1985 |
xx |
-2 |
1995 |
xx |
6 |
2005 |
xx |
13 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2008, 2007,2005,1998,1989,1988,1973,1970,1969. 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):
-1.44 |
-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 |
One month 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 |
Two 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 |
Three 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 |
Four months ago:
|
0.06 |
0.02 |
-0.1 |
-0.29 |
-0.43 |
-0.6 |
-0.84 |
-1.06 |
-1.17 |
-1.14 |
-0.92 |
-0.66 |
-0.45 |
-0.33 |
-0.27 |
-0.15 |
-0.07 |
-0.01 |
-0.06 |
-0.15 |
-0.24 |
|
MJJ |
JAS |
SON11 |
NDJ |
JFM11 |
MAM |
MJJ |
JAS |
SON |
NDJ |
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Anomalies relative to
1971-2000 climo.