During June 2019, the atmosphere continued to respond to a warm pool of water in the central and western Pacific, with above normal rainfall and cloud centred along and just west of the International Dateline. Rainfall and sea surface temperature (SST) patterns remained consistent with weak, central Pacific El Niño conditions.
The NINO3.4 index SST anomaly (in the central Pacific) for June was +0.75°C, which was similar to May. The NINO1+2 index (in the far eastern Pacific) was near normal. The Southern Oscillation Index (SOI) was -0.7 in June, which was the same value as May. The conventional threshold for El Niño (SOI values below -1.0 for three consecutive months) has not been reached, but a weakly coupled central-based El Niño remains present.
According to the consensus from international models, the probabilityfor oceanic El Niño conditions is 60% for the July –September period. Beyond this, for the October –December period, the probability for oceanic El Niño conditions is the same at 60%. For January –March 2020, the probability for El Niño increases to 65%. This continues to suggest the occurrence of a ‘protracted’ weak event (multi-year duration).