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Ocean trends suggest wet weather to continue

Posted on Wednesday, 19 October 2016 by walter

Two climate drivers monitored by the Bureau of Meteorology suggest little change to the rainy weather pattern that delivered Australia’s wettest May-September on record.

It says warmer than average Pacific Ocean sea surface temperatures to Australia’s north and east point to La Nina-like impacts such as higher rainfall, even if an event does not fully develop.

Two of eight international climate models suggest brief, weak La Nina levels are possible towards the end of the year, while the remainder flag neutral levels to the end of summer.

To Australia’s west there is an easing of the negative Indian Ocean Dipole (IOD) pattern, which also brings rain, but any effect from the change may be muted.

“Negative IOD values have eased over the past fortnight,” the bureau said last week. “However, this is mainly due to ocean warming off Africa.

“Waters off Indonesia remain very warm, and were the second-warmest on record for September. This may see continued IOD impacts for Australia.”

Models indicate the IOD will return to neutral levels by the end of spring.

Australia had its second-wettest September on record, with rainfall just below 2010 levels, continuing a series of monthly drenchings that began in May as an El Nino in the Pacific Ocean broke down.

The IOD index also reached some of its lowest values since reliable records began in 1960.

The May-September national average rainfall of 213.24mm easily surpassed the previous record of 191.87mm, set in 1978.