HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -0.50 for AMJ2011, down from MAM. La Nina has weakened to the point of the present state being neutral, not unusual for the season of course.
The CA method, acting on global AMJ2011 seasonal means as latest input, has most of its members on the cold side of neutral. La Nina conditions, but weaker and only in a few members, are expected by CA for rest of 2011, with a slight increase in coolness towards the end of the year. Thus there could a weak return of La Nina next winter. Some members crawl into positive territory by early spring 2012. Spread is high and peculiar with some members that go warmest first and end coldest (and vice versa), see graphic sst1.gif
Weights have changed only modestly. There are nine years with high +ve weight!, and eight high -ve weight. OCN flavor is much reduced, with more +ve weight given to older years than ever before and a high –ve weight to 2004. Also note the string of negative weights for 1985 to 1995, a strong sign of 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 MJJ2010 thru AMJ2011). 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 June 2011.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
0 |
1966 |
xx |
-8 |
1976 |
xx |
11 |
1986 |
xx |
-10 |
1996 |
xx |
13 |
2006 |
xx |
11 |
1957 |
xx |
-4 |
1967 |
xx |
2 |
1977 |
xx |
-7 |
1987 |
xx |
-10 |
1997 |
xx |
3 |
2007 |
xx |
-2 |
1958 |
xx |
-5 |
1968 |
xx |
-10 |
1978 |
xx |
4 |
1988 |
xx |
-8 |
1998 |
xx |
-6 |
2008 |
xx |
15 |
1959 |
xx |
-6 |
1969 |
xx |
8 |
1979 |
xx |
4 |
1989 |
xx |
3 |
1999 |
xx |
3 |
2009 |
xx |
9 |
1960 |
xx |
-16 |
1970 |
xx |
6 |
1980 |
xx |
1 |
1990 |
xx |
0 |
2000 |
xx |
11 |
2010 |
xx |
12 |
1961 |
xx |
-4 |
1971 |
xx |
6 |
1981 |
xx |
6 |
1991 |
xx |
-4 |
2001 |
xx |
-7 |
2011 |
xx |
NA |
1962 |
xx |
12 |
1972 |
xx |
1 |
1982 |
xx |
2 |
1992 |
xx |
-14 |
2002 |
xx |
3 |
xx |
Xx |
|
1963 |
xx |
13 |
1973 |
xx |
-5 |
1983 |
xx
|
3 |
1993 |
xx |
-8 |
2003 |
xx |
-9 |
xx |
Xx |
|
1964 |
xx |
-8 |
1974 |
xx |
16 |
1984 |
xx |
-2 |
1994 |
xx |
-15 |
2004 |
xx |
-10 |
xx |
Xx |
|
1965 |
xx |
-10 |
1975 |
xx |
3 |
1985 |
xx |
-5 |
1995 |
xx |
-7 |
2005 |
xx |
5 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2010,2008,2006,2000,1996,1976,1974,1963,1962. Weights are high -ve (< - 0.10) for 2004,1994,1992,1987,1986,1968,1966,1960.
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
-0.5 |
-0.48 |
-0.38 |
-0.29 |
-0.28 |
-0.31 |
-0.38 |
-0.43 |
-0.47 |
-0.44 |
-0.41 |
-0.33 |
-0.24 |
-0.15 |
-0.07 |
0.02 |
0.09 |
0.19 |
0.28 |
0.34 |
0.38 |
MJJ11 |
JAS |
SON |
NDJ |
JFM12 |
MAM |
MJJ12 |
JAS |
SON |
NDJ |
2013 |
One month ago:
-0.74 |
-0.69 |
-0.51 |
-0.23 |
-0.16 |
-0.15 |
-0.19 |
-0.27 |
-0.31 |
-0.36 |
-0.35 |
-0.34 |
-0.32 |
-0.32 |
-0.25 |
-0.18 |
-0.07 |
-0.02 |
0.01 |
0.01 |
0.03 |
MAM |
MJJ11 |
JAS |
SON |
NDJ |
JFM12 |
MAM |
MJJ |
JAS |
SON12 |
NDJ |
Two months ago:
-1.02 |
-0.97 |
-0.74 |
-0.45 |
-0.33 |
-0.25 |
-0.26 |
-0.33 |
-0.45 |
-0.48 |
-0.47 |
-0.4 |
-0.34 |
-0.26 |
-0.25 |
-0.18 |
-0.13 |
-0.01 |
0.06 |
0.11 |
0.12 |
MAM11 |
MJJ |
JAS |
SON |
NDJ |
JFM |
MAM12 |
MJJ |
JAS |
SON |
Three months ago:
-1.26 |
-1.23 |
-1.01 |
-0.64 |
-0.49 |
-0.41 |
-0.36 |
-0.38 |
-0.43 |
-0.54 |
-0.54 |
-0.49 |
-0.36 |
-0.18 |
-0.06 |
-0.02 |
0.03 |
0.06 |
0.18 |
0.25 |
0.32 |
JFM11 |
MAM |
MJJ |
JAS |
SON11 |
NDJ |
JFM12 |
MAM |
MJJ |
JAS |
Four months ago:
-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 |
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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