HIGHLIGHT: The seasonal mean NINO3.4 anomaly was positive at 0.76 C for NDJ2014/15, unchanged from OND, and the third running 3-month mean > 0.5C.
The CA method, acting on global NDJ2014/15 seasonal means as latest input, but using a string of global SST going back one year, has all of its members staying positive until MAM 2015. By that time all members will have fallen below 0.5C. The ensemble mean has already peaked at about 0.75 in NDJ2014/15. So much for a very weak warm event in winter 2014/15 in terms of Nino34 SST. CA-SST is non-committal about what might happen later in 2015, but if anything slightly +ve.
Weights were stable from last month. There are 8 (5) large +ve (-ve) weights in excess of abs(0.10). Four years in the 1956-1965 decade have unusually high weights (like 1959 +0.19 and 1964 -0.16) – this old decade has only recently become so important in constructing the analogue. Moreover, 1957, 1958 and 1959 are ALL strongly positive, so in addition to interannual, the interdecadal plays a big role here.
Announcement: Next month, data thru DJF2014/15, the covariance matrix will be upped by one. This could lead, potentially, to rather big changes assigned to individual years.
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 DJF2014 thru NDJ2014). Years in the table are labeled by the year of the middle month of the most recent predictor season. Weights for 1956 and 2013 are less (by 50%) because only half the members use these years ("early" members use 1956, "late" members 2013). Data currently thru Jan 2015. Next month the year 2014 will have a weight in this table.
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Wgt |
Year |
IP |
Weigt |
1956 |
xx |
-6 |
1966 |
xx |
-5 |
1976 |
Xx |
10 |
1986 |
xx |
10 |
1996 |
xx |
1 |
2006 |
xx |
0 |
1957 |
xx |
13 |
1967 |
xx |
9 |
1977 |
Xx |
3 |
1987 |
xx |
-11 |
1997 |
xx |
1 |
2007 |
xx |
7 |
1958 |
xx |
13 |
1968 |
xx |
-9 |
1978 |
Xx |
-4 |
1988 |
xx |
-5 |
1998 |
xx |
-13 |
2008 |
xx |
-2 |
1959 |
xx |
19 |
1969 |
xx |
1 |
1979 |
Xx |
4 |
1989 |
xx |
1 |
1999 |
xx |
-15 |
2009 |
xx |
9 |
1960 |
xx |
-5 |
1970 |
xx |
-2 |
1980 |
Xx |
0 |
1990 |
xx |
2 |
2000 |
xx |
-4 |
2010 |
xx |
3 |
1961 |
xx |
1 |
1971 |
xx |
-16 |
1981 |
Xx |
-5 |
1991 |
xx |
-3 |
2001 |
xx |
5 |
2011 |
xx |
12 |
1962 |
xx |
-1 |
1972 |
xx |
-3 |
1982 |
Xx |
-4 |
1992 |
xx |
1 |
2002 |
xx |
9 |
2012 |
xx |
12 |
1963 |
xx |
-3 |
1973 |
xx |
-3 |
1983 |
xx |
3 |
1993 |
xx |
1 |
2003 |
xx |
9 |
2013 |
xx |
10 |
1964 |
xx |
-16 |
1974 |
xx |
7 |
1984 |
Xx |
-4 |
1994 |
xx |
-3 |
2004 |
xx |
-3 |
2014 |
xx |
NA |
1965 |
xx |
-8 |
1975 |
xx |
-1 |
1985 |
Xx |
-3 |
1995 |
xx |
5 |
2005 |
xx |
7 |
xx |
Xx |
Weights are high +ve (>+0.10) for 2013,2012,2011,1986,1976,1959,1958,1957
Weights are high -ve (< - 0.10) for 1999,1998,1987,1971,1964
Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):
0.76 |
0.72 |
0.59 |
0.34 |
0.28 |
0.23 |
0.22 |
0.19 |
0.12 |
0.09 |
0.14 |
0.19 |
0.17 |
0.05 |
-0.04 |
0 |
0.08 |
0.12 |
0.12 |
0.11 |
0.18 |
NDJ |
JFM15 |
MAM |
MJJ |
JAS |
SON15 |
NDJ |
JFM16 |
MAM |
MJJ |
JAS |
One month ago:
0.75 |
0.77 |
0.68 |
0.5 |
0.32 |
0.25 |
0.19 |
0.19 |
0.17 |
0.15 |
0.13 |
0.21 |
0.25 |
0.14 |
-0.01 |
-0.06 |
0.01 |
0.11 |
0.14 |
0.11 |
0.05 |
NDJ |
JFM15 |
MAM |
MJJ |
JAS |
SON15 |
NDJ |
JFM16 |
MAM |
MJJ |
Two months ago
0.6 |
0.66 |
0.78 |
0.76 |
0.63 |
0.46 |
0.38 |
0.29 |
0.25 |
0.17 |
0.17 |
0.18 |
0.25 |
0.25 |
0.19 |
0.07 |
0.02 |
0.09 |
0.16 |
0.12 |
-0.02 |
SON |
NDJ |
JFM15 |
MAM |
MJJ |
JAS |
SON15 |
NDJ |
JFM16 |
MAM |
MJJ |
Three months ago:
0.35 |
0.41 |
0.63 |
0.92 |
0.88 |
0.8 |
0.65 |
0.58 |
0.45 |
0.35 |
0.19 |
0.14 |
0.13 |
0.21 |
0.31 |
0.29 |
0.2 |
0.14 |
0.19 |
0.25 |
0.2 |
SON |
NDJ |
JFM15 |
MAM |
MJJ |
JAS |
SON15 |
NDJ |
JFM16 |
MAM |
Four months ago
0.28 |
0.3 |
0.44 |
0.73 |
0.88 |
0.88 |
0.83 |
0.7 |
0.66 |
0.56 |
0.46 |
0.28 |
0.19 |
0.2 |
0.34 |
0.53 |
0.56 |
0.46 |
0.32 |
0.28 |
0.26 |
JAS |
SON |
NDJ |
JFM |
MAM |
MJJ |
JAS |
SON15 |
NDJ |
JFM16 |
MAM |
Anomalies relative to 1981-2010 climo.