El Nino watch underway as La Nina comes to end following three wet years

La Nina has officially been declared over after months of easing and an El Nino watch is now underway.

More rain is typical during La Nina while El Nino often means a hotter, drier climate, as was experienced throughout summer in Europe.

Andrew Watkins, Bureau of Meteorology spokesman, said after three years of record-breaking rainfall in eastern Australia, long-range forecasting showed drier than average conditions for most of the country this autumn.

Dr Watkins said El Nino didn't necessarily mean drought conditions for Australia in 2023.

"There have been 27 El Nino years since 1900, and around 18 of those years were affected by widespread winter-spring drought," he said.

Dr Watkins said while long-range forecasts showed an increased chance of below average rainfall for most of Australia during autumn, the northern wet season continued.

He said the wet season, which included the tropical cyclone season for northern Australia, was likely continuing into April.

"There remains the chance of tropical weather systems bringing heavy rain at times to the north," Dr Watkins said.

If these tropical weather systems extend south, there remains the possibility of periods of heavy rainfall, and flooding, particularly in parts of eastern Australia where soils remain wet and rivers and dams are still full, the bureau says.

Kimberley Reid, atmospheric scientist at Monash University, said the Earth's climate was like a pendulum.

"It's not that unusual to swing into an El Nino after a La Nina," Dr Reid said.

"Now is the time to start cutting back the excess vegetation that grew over the last three years.

"All it takes is a dry winter and spring, which is probable with an El Nino, and all that excess vegetation will be fuel for summer bushfires."

IN OTHER NEWS:

La Nina is the cool phase of the El Nino-Southern Oscillation, while El Nino is the warm phase.

El Nino-Southern Oscillation describes a naturally occurring cycle in the climate system, including the location of warmer or cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean, and its connection with the trade winds and patterns in the atmosphere.

Its effects impact weather around large parts of the globe, including Australia.

If the chance of El Nino forming in 2023 increases to 70 per cent, the bureau will change from watch to alert status.