DAFWA forecasts contrast with wetter bureau outlook

If you felt buoyed by Bureau of Meteorology predictions this year might have a wetter-than-average autumn break, you may want to think again.

The Department of Agriculture and Food has released its three-month seasonal outlook, and its predictions are much less attractive for the northern, eastern and south-eastern agricultural zones.

According to DAFWA climate research officer Fiona Evans, the department's statistical modelling shows a 60-70 per cent chance of a dryer-than-average March, April and May for those particular areas.

Dr Evans believes the department's modelling techniques have proven to be more accurate in the last few decades than the bureau's.

But Dr Evans said DAFWA's seasonal forecasts showed a normal weather pattern for all other areas, including the Great Southern, the South West, and parts of the Central Wheatbelt.

Speaking at the Liebe Group's recent Crop Update meeting in Dalwallinu, Dr Evans said DAFWA had invested significant funds into developing its statistical modelling forecasting system.

"Growers need this information, so we put a lot of time and effort into developing our own forecasting systems," she said.

"But we always present the Bureau's information as well, so it's not a competitive situation."

Dr Evans said in terms of accuracy, the models were two of the best systems in the world at forecasting rainfall in the south-west.

The bureau's model is predicting a 60-70 per cent chance of a wetter-than-average three-month autumn period across WA's agricultural area.

Bureau of Meteorology senior climate liaison officer Glenn Cook previously warned growers the accuracy of the bureau's outlook was typically lower at this time of year.

Dr Evans said the forecasts were not providing much information on which to base rainfall predictions, with the Indian Ocean dipole in a neutral mode.

"Really, all of the models are hedging their bets at the moment," she said.

Dr Evans said some models were predicting an El Nino pattern for 2014, but this would not necessarily affect WA rainfall.

"El Nino is associated with drier conditions in the Eastern States, but not here in WA," she said.

"If you look at the two models in combination and the fact El Nino is not likely to have a significant impact on our rainfall here in WA, the odds are equally likely for both drier and wetter conditions for the three months ahead."

Dr Evans cautioned that while growers should consider seasonal forecasts, it was just as important to look at currently measurable information.

"I think what they need to be doing is looking at the information they can measure now," she said.