MELBOURNE, Australia – El Niño continues in the tropical Pacific Ocean reports the Bureau of Meteorology of the Australian Government in its latest update. Model forecasts and observations indicate sea surface temperatures in the central tropical Pacific have peaked and are now declining. Sea surface temperatures in the tropical Pacific are expected to return to neutral El Niño–Southern Oscillation (ENSO) levels in the southern hemisphere autumn 2024.
Most atmospheric indicators are close to normal levels, although trade winds have temporarily weakened in line with the passage of the Madden-Julian Oscillation through the region.
The Indian Ocean Dipole (IOD) has returned to neutral, with the latest weekly IOD index (to 4 February 2024) being below +0.4 °C (the positive IOD threshold) for the second consecutive week. IOD events typically break down as the monsoon trough shifts south into the southern hemisphere.
Due to the strength of the positive IOD in 2023, the event decay has been later than usual.
The majority of model forecasts indicate the IOD will be neutral until at least April, consistent with the annual cycle of the IOD.
The Southern Annular Mode (SAM) is currently neutral. Forecasts suggest it will remain mostly neutral over the coming fortnight. Neutral SAM has little influence on Australian rainfall patterns.
The Madden–Julian Oscillation (MJO) is currently over the central Pacific. International climate models suggest the MJO is likely to remain in the central Pacific during the coming fortnight. When the MJO is in the central Pacific region, it may also weaken trade winds in the central to western Pacific, which is likely to temporarily stall cooling SSTs associated with El Nino decline; SSTs across parts of the Pacific have indeed increased slightly over the past week.
The World Meteorological Organization (WMO) has confirmed that 2023 was the warmest year on record. The WMO estimated global temperatures in 2023 were 1.45 ± 0.12 °C above the 1850–1900 average, exceeding the previous record warm years of 2016 and 2020, with 1.29 ± 0.12 °C and 1.27 ± 0.12°C respectively.
Global sea surface temperatures (SSTs) were highest on record for all respective months between April 2023 and January 2024.
Australia’s climate has warmed by 1.48 ± 0.23 °C between 1910 and 2022, leading to an increase in the frequency of extreme heat events. In recent decades, there has also been a trend towards a greater proportion of rainfall from high intensity, short duration rainfall events, especially across northern Australia during the wet season.