Renewed sea surface warming has again raised the chances Australia will be affected by a drought-inducing El Nino.
The Bureau of Meteorology says the sea surface on central and western parts of the tropical Pacific Ocean – a key indicator if the presence of an El Nino – have warmed by 0.2C to 0.3C in the past two weeks, with average temperatures for this part of the year in the region now about 2C above normal.
This has prompted the BOM prompted to change its El Nino Southern Oscillation tracker prediction from neutral to watch, just two positions short of the declaration of an El Nino event.
“This is largely the result of weakened trade winds and tropical surface currents in recent weeks. Weakened trade winds are forecast to continue, and this may induce further warming,” the BOM said in its fortnightly ENSO report.
El Ninos typically result in below-average winter and spring rainfall in eastern Australia and warmer than normal temperatures in the southern half of the continent.
Many parts of Queensland, NSW, Victoria and South Australia are already suffering a prolonged dry spell.
The BOM says all eight international weather forecasting models it surveys predict sea surface temperatures are likely to remain warmer than average.
Although the accuracy of the forecast is less reliable during the southern winter, the BOM says six of the eight models suggest indicate sea surface temperatures will exceed El Nino thresholds by mid-year.
Tropical Pacific sea surface temperatures have been highly variable variable since late 2014.
In January, following a dramatic cooling of temperatures, the BOM moved its ENSO tracker from alert, one step short of declaring an El Nino, to neutral, with a less than 25 per cent chance an El Nino would develop by winter,