HIGHLIGHT: The seasonal mean NINO3.4 anomaly was 2.2 C for ASO2015, clearly up from JAS (1.9). And very impressive numbers for this time of year. The maximum in observed interannual standard deviation is 3 months away (NDJ). Usually this is the time for events to peak, but no guarantee.

The CA method, acting on global ASO2015 seasonal means as latest input, but using a string of global SST going back one year, has all of its members, staying >1.0 for Nino34 from now thru MAM2016. By NDJ 2015 all members are > 2.3 (which would be tying the record) , and a few reaching near 3.0C. An unbelievably strong forecast by any standard, but certainly by a statistical method. Then a significant cool down in 2016, ensemble mean -1.10 by fall 2016.

Weights were stable from last month. There are 6 (7) large +ve (-ve) weights in excess of abs(0.10). Of the historically strong warm event years (57, 72, 82, 97) the weights are 0.04, 0.02, 0.06 and 0.24 respectively. The weight for 1997 is really high now and, as of now, the situation is evolving more towards a 97/98 event. Five years in the 1957-1966 decade have unusually high weights (like 1959 +0.18 and 1965 -0.12) – this old decade has only recently become so important in constructing the analogue. Moreover, 1964-1966 are all strongly -ve, so in addition to interannual, the interdecadal plays a big role here. Noteworthy is also the high weight for 2014. The last year is used in only 6 of the 12 construction so 0.18 is doubly impressive. In the 6 constructions the year 2014 was used in, the weight was anywhere from 0.28 to 0.41.

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 SON2014 thru ASO2015). Years in the table are labeled by the year of the middle month of the most recent predictor season. Weights for 1956 and 2014 are less (by 50%) because only half the members use these years ("early" members use 1956, "late" members 2014). Data currently thru Oct 2015.

Year	IP	Wgt	Year	IP	Wgt	Year	IP	Wgt	Year	IP	Wgt	Year	IP	Wgt	Year	IP	Weigt
1956	xx	-8	1966	Xx	-10	1976	Xx	2	1986	xx	3	1996	xx	-3	2006	xx	0
1957	xx	4	1967	Xx	11	1977	Xx	2	1987	xx	6	1997	xx	24	2007	xx	-8
1958	xx	11	1968	Xx	5	1978	Xx	-4	1988	xx	-8	1998	xx	2	2008	xx	-2
1959	xx	18	1969	Xx	3	1979	Xx	2	1989	xx	-4	1999	xx	-15	2009	xx	10
1960	xx	-1	1970	Xx	-5	1980	Xx	-3	1990	xx	-4	2000	xx	-4	2010	xx	3
1961	xx	-4	1971	Xx	-6	1981	Xx	-8	1991	xx	3	2001	xx	1	2011	xx	2
1962	xx	4	1972	Xx	2	1982	Xx	6	1992	xx	1	2002	xx	8	2012	xx	3
1963	xx	6	1973	Xx	-12	1983	xx	3	1993	xx	-11	2003	xx	6	2013	xx	8
1964	xx	-12	1974	Xx	-2	1984	Xx	-16	1994	xx	8	2004	xx	6	2014	xx	18
1965	xx	-12	1975	Xx	-8	1985	Xx	3	1995	xx	-5	2005	xx	-5	2015	xx	NA

Weights are high +ve (>+0.10) for 2014, 2009,1997,1967,1959,1958

Weights are high -ve (< - 0.10) for 1999,1993,1984,1973,1966,1965,1964

Ens ave Nino34 anomaly forecasts, for leads -3, -2, -1, 0 etc: in plain numbers (ensemble mean):

2.2	2.26	2.6	2.96	2.73	2.27	1.66	1.12	0.56	0.13	-0.26	-0.37	-0.46	-0.86	-1	-1.09	-1.03	-0.87	-0.61	-0.39	-0.31
	SON15		NDJ		JFM16		MAM		MJJ		JAS		SON		NDJ		JFM		MAM

One month ago

1.89	1.89	2.14	2.7	2.91	2.76	2.35	1.77	1.23	0.65	0.16	-0.27	-0.41	-0.78	-0.82	-0.89	-0.93	-0.86	-0.72	-0.49	-0.3
JAS		SON15		NDJ		JFM16		MAM		MJJ		JAS16		SON		NDJ		JFM17		MAM

Two months ago:

1.65	1.62	1.77	2.25	2.7	2.91	2.77	2.36	1.79	1.26	0.7	0.24	-0.15	-0.58	-0.67	-0.69	-0.74	-0.76	-0.69	-0.59	-0.39
	JAS		SON		NDJ		JFM2016		MAM		MJJ		JAS		SON		NDJ		JFM2017

Three months ago

1.21	1.19	1.23	1.48	1.89	2.32	2.5	2.39	2.06	1.62	1.22	0.76	0.32	-0.31	-0.47	-0.53	-0.54	-0.57	-0.57	-0.51	-0.45
MJJ		JAS		SON15		NDJ		JFM16		MAM		MJJ		JAS		SON		NDJ		JFM17

Four months ago:

0.96	0.95	0.94	0.93	1.12	1.47	1.88	2.05	1.97	1.7	1.36	1.04	0.64	0.1	-0.28	-0.39	-0.43	-0.45	-0.5	-0.48	-0.43
	MJJ		JAS		SON2015		NDJ		JFM2016		MAM		MJJ		JAS		SON		NDJ

Anomalies relative to 1981-2010 climo.