Neutral conditions prevail but whisper of hope for wet winter

Neutral conditions prevail but whisper of hope for wet winter

Weather
Aussie farmers are hoping that the small whispers of a potential wet season ahead amplify over coming months.

Aussie farmers are hoping that the small whispers of a potential wet season ahead amplify over coming months.

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It's mostly all neutral out of both the Pacific and Indian Oceans on the climate front, but some models are picking up promising signals.

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THE EL Nino / Southern Oscillation (ENSO), the major climate driver out of the Pacific Ocean remains firmly in neutral territory, but long-term climate models are sensing just a whisper of activity that could get Australian farmers excited.

In its fortnightly climate update the Bureau of Meteorology (BOM) said all drivers of ENSO, including the Southern Oscillation Index (SOI), trade winds, cloudiness near the Date Line, and sea surface and sub-surface temperatures in the tropical Pacific Ocean all were neutral.

It meant six of the eight climate models used by the BOM forecast neutral conditions right through the winter.

However, the other two fell on the side of a La Nina event, correlated with wetter than average conditions.

It is a similar story in the Indian Ocean, where most models are forecasting neutral Indian Ocean Dipole (IOD) conditions, but a couple are forecasting a negative IOD, tied in with wetter weather in Australia.

Dale Grey, of Agriculture Victoria and member of The Break climate analysis team, said it the same with the models he had reviewed, with most neutral but a few forecasting a potential La Nina and a negative IOD.

"In terms of a La Nina, things are primed with generally more cool water than warm, from which four models are getting sniffs of a possible La Nina," Mr Grey said.

However, both Mr Grey and the BOM cautioned that ENSO forecasts have their lowest skill during the autumn months.

"Given current conditions, history shows anything is possible in the central Pacific from here," Mr Grey said

On the other side of the continent, the Indian Ocean Dipole (IOD) is neutral, but again there are some very early signs of promise.

The BOM said most the international climate models surveyed were neutral, with one model briefly reaches positive levels, correlated with dry conditions, at the end of autumn, while several tend towards negative levels during the southern hemisphere winter.

However, it warned, similar to ENSO, the accuracy of IOD forecasts beyond autumn is low.

In terms of medium term rainfall, Mr Grey said rainfall triggers mechanisms such as the Southern Annular Mode (SAM) were showing drier tendencies, while pressure patterns are now in a summer pattern forcing fronts and lows further south, where pressure has been higher.

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