THE Bureau of Meteorology’s ”ENSO Outlook” is at  the “alert” stage in forecasting La Niña conditions – above-average rainfall for northern and eastern Australia – during spring and summer.

This is due to continued cooling in the tropical Pacific Ocean and climate models showing sustained La Niña conditions over summer.

BOM says that in the past when La Niña ”alert” criteria is met, La Niña has subsequently developed around 70 per cent of the time; this is about triple the normal likelihood. 

“Sea surface temperatures in the central tropical Pacific Ocean have cooled over the past three months, edging closer to La Niña levels,” the bureau says.

“These cooler surface waters are supported by cooler than average waters beneath the surface. Some atmospheric indicators, such as the Southern Oscillation Index (SOI) and cloudiness near the Date Line, are approaching La Niña levels. Most international climate models surveyed by the bureau indicate weak La Niña conditions are likely for the coming months.

“Climate change continues to influence Australian and global climate. Australia’s climate has warmed by around 1.44°C for the 1910–2019 period. Rainfall across northern Australia during its wet season (October–April) has increased since the late 1990s. In recent decades there has been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia.”