Strongest El Nino conditions since 1997 continue to weaken

THE strongest El Nino in more than a decade is continuing to weaken.

El Nino continues to weaken

THE strongest El Nino in more than a decade is continuing to weaken.

In an official update yesterday, the Bureau of Meteorology said while the El Nino remained strong it continued a “gradual decline”.

Its climate models suggest a return to neutral levels in the second quarter of this year, with the surface of the Pacific Ocean close to the equator cooling 0.5C since the El Nino peaked late last year.

El Nino conditions last year were described as the strongest since 1997.

Its effects were most damaging in the Wimmera and Mallee, with many grain growers forced to cut crops for hay, rather than take them through to harvest, following a five-day heatwave last October in which temperatures nudged 40C.

“Below the ocean surface, cooler than average waters now extend into the central tropical Pacific Ocean,” the BOM said.

“In the atmosphere, trade winds have recently returned to near-normal levels in the central and eastern Pacific, although the Southern Oscillation Index has been strongly negative in recent weeks.”

The BOM said about 50 per cent of the 26 El Nino events since 1900 had been followed by a neutral year, with 40 per cent followed by a wetter-than-average La Nina.

“Models suggest the neutral state is the most likely for the second half of 2016, followed by a La Nina, with a repeat El Nino assessed as very unlikely,” it said.

“Historically, the breakdown of strong El Nino events brings above-average rainfall to some, but not all, of Australia in the first half of the year.”

The BOM said the Indian Ocean Dipole has little influence on Australian climate between December and April “however Indian Ocean sea surface temperatures remain very warm across the majority of the basin which may provide extra moisture for rain systems across Australia”.