An alert system for the El Niño–Southern Oscillation
The ENSO Outlook remains at El Niño WATCH. This means that while the El Niño–Southern Oscillation is currently neutral, there is approximately a 50% chance that El Niño may develop later in 2023. This is about twice the normal likelihood.
A significant amount of warmer than average water exists in the sub-surface of the western and central tropical Pacific Ocean, and warm sea surface temperatures (SST) anomalies continue to strengthen in the eastern tropical Pacific. The Southern Oscillation Index (SOI) has decreased to negative values over the past fortnight. Warming ocean temperatures in the eastern and central tropical Pacific and decreasing SOI values can be a precursor of El Niño development.
El Niño WATCH is not a guarantee that El Niño will occur, rather an indication that some of the typical precursors are currently occurring. All climate models surveyed by the Bureau suggest that El Niño thresholds are likely to be approached or exceeded during the southern hemisphere winter.