El Nino alert remains with expected increases in temperatures and lower rainfall across southern WA

Warmer and drier conditions can be expected through September to November after the Bureau of Meteorology’s latest Climate Driver Update remained at El Niño Alert.

The latest long-range forecast for September to November, released August 15, determined that rainfall was likely to be below average, by 60 per cent to greater than 80 per cent, for much of the eastern half of Australia and southern Western Australia.

There was also a higher than usual, greater than 80 per cent chance, that “maximum temperatures are very likely for almost all of Australia”.

Department of Primary Industries and Regional Development climatologist Ian Foster said the weather had been drier than normal for northern and eastern agricultural areas and parts of the south-west since April, while the coastal parts of the south coast had been wetter.

Mr Foster said the predicted El Nino weather brought “a risk to spring conditions for crops that are currently under water stress, as well as those where development has been slow to date”.

“Crop and pasture development has slowed since April as accumulated thermal time has been well below normal for most of the agricultural area,’ he said.

“June was particularly cold, with frosts in July and into August.

“In late August, there is an increased risk of unusually warm daytime temperatures for central and northern agricultural areas, while low temperatures are expected to be near normal for this period.”

BoM senior climatologist Catherine Ganter said the atmospheric changes usually expected during El Niño had so far not occurred, although an El Nino watch was issued on March 14 and developed into an alert on June 6.

“Atmospheric indicators of El Niño include wind, cloud and broad-scale pressure patterns across the Pacific Ocean,” Ms Ganter said.

“While the past fortnight has seen a decrease in Southern Oscillation Index values to El Niño-like values, this strong swing has been due to more localised higher than average pressure in Darwin, rather than a broader El Niño signal.

“Overall, the atmospheric indicators suggest the Pacific Ocean and atmosphere are not yet consistently reinforcing each other as occurs during El Niño events.”

The status of the El Niño–Southern Oscillation Outlook is determined using set criteria and expert analysis by climatologists at the bureau.

She said the United States, Japan and Australia each had slightly different metrics for monitoring and declaring ENSO events.

When El Niño Alert criteria have been met in the past, an El Niño event has developed around 70 per cent of the time — although each event is different and its impact can vary.

El Niño events increase the risk of extreme temperatures, such as heatwaves and hotter days.

Ms Ganter said BoM was keeping a close eye on the situation and was regularly monitoring conditions in the tropical Pacific Ocean.