ENSO Prediction: The Summer (JJA) Oceanic Nino Index used as a harbinger for El Niño and La Nina Events.

The JJA or Summer Oceanic Nino Index seems to be a predictor for later in the year La Nina's and El Niño's. The JJA ONI at certain thresholds in the negative (La Nina) and the positive (El Niño) can act as a predictor for the definition of ENSO events where the ONI is +/-0.5 consecutively for 5 trimonthly periods or more.

The El Niño Indicator: 100% of the time since 1950 , if the JJA ONI is +0.4 or higher while excluding the years that already have El Niño's occurring through the year (1958, 1969, 1987), then an El Niño will have started by MAM to ASO. Half of the years end up having Strong El Niño Status.

 

 

The La Nina Indicator: 100% of the time since 1950, If an El Niño ends at the beginning of the year, and the ONI for the trimonthly period of JJA is -0.4 or less, then a La Nina will have already started by AMJ to JAS. 5 out of 7 of the La Nina's end up Strong.