HIGHLIGHT: The seasonal mean NINO3.4 anomaly was -0.30 for MJJ2011, down from AMJ. Last winter’s 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 MJJ2011 seasonal means as latest input, has all of its members on the cold side of neutral. La Nina conditions, but weaker and only in a few members, are expected by CA to return for the later part 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 hesitantly into positive territory by 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 eight 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, aside from interannual, the strong sign of interdecadal variation, with +ve in the 2000s and around 1970, and –ve around 1990 and early sixties.
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 JJA2010 thru MJJ2011). 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 July 2011.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP
|
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
2 |
1966 |
xx |
-8 |
1976 |
xx |
13 |
1986 |
xx |
-13 |
1996 |
xx |
7 |
2006 |
xx |
13 |
1957 |
xx |
-3 |
1967 |
xx |
2 |
1977 |
xx |
-3 |
1987 |
xx |
-8 |
1997 |
xx |
0 |
2007 |
xx |
-2 |
1958 |
xx |
-4 |
1968 |
xx |
-10 |
1978 |
xx |
-1 |
1988 |
xx |
-5 |
1998 |
xx |
-7 |
2008 |
xx |
10 |
1959 |
xx |
-7 |
1969 |
xx |
8 |
1979 |
xx |
4 |
1989 |
xx |
5 |
1999 |
xx |
3 |
2009 |
xx |
9 |
1960 |
xx |
-13 |
1970 |
xx |
6 |
1980 |
xx |
-1 |
1990 |
xx |
5 |
2000 |
xx |
16 |
2010 |
xx |
14 |
1961 |
xx |
-2 |
1971 |
xx |
8 |
1981 |
xx |
0 |
1991 |
xx |
-3 |
2001 |
xx |
-5 |
2011 |
xx |
NA |
1962 |
xx |
10 |
1972 |
xx |
2 |
1982 |
xx |
3 |
1992 |
xx |
-16 |
2002 |
xx |
2 |
xx |
Xx |
|
1963 |
xx |
9 |
1973 |
xx |
-3 |
1983 |
xx
|
2 |
1993 |
xx |
-7 |
2003 |
xx |
-12 |
xx |
Xx |
|
1964 |
xx |
-3 |
1974 |
xx |
10 |
1984 |
xx |
-7 |
1994 |
xx |
-14 |
2004 |
xx |
-8 |
xx |
Xx |
|
1965 |
xx |
-10 |
1975 |
xx |
2 |
1985 |
xx |
-4 |
1995 |
xx |
-12 |
2005 |
xx |
12 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2010,2008,2006,2005,2000,1976,1974,1962.
Weights are high -ve (< - 0.10) for 2003,1995,1994,1992,1986,1968,1965,1960.
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
-0.31 |
-0.31 |
-0.29 |
-0.26 |
-0.28 |
-0.33 |
-0.38 |
-0.42 |
-0.4 |
-0.37 |
-0.32 |
-0.22 |
-0.14 |
-0.12 |
-0.1 |
-0.04 |
0.06 |
0.17 |
0.25 |
0.3 |
0.26 |
MJJ11 |
JAS11 |
SON11 |
NDJ |
JFM |
MAM |
MJJ |
JAS12 |
SON |
NDJ |
JFM13 |
One month ago:
-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 |
Two months 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 |
Three 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 |
Four 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 |
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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