Forecasts show an increased chance of wetter than normal conditions during early autumn for eastern and southern parts of the Wheatbelt, but there may be fewer opportunities for early sowing.
The Department of Agriculture and Food presented its latest Statistical Seasonal Forecast (SFF) information at the Agribusiness Crop Updates event in Perth.
Department research officer Fiona Evans said forecasts were in the form of probability distributions indicating shifts away from long-term averages, and could also provide information on the likelihood of these shifts occurring.
“The forecast for February to April indicates a 40-60 per cent chance of exceeding the long term (1975-2011) median rainfall for the higher rainfall areas of the Wheatbelt, with a 60-80 per cent chance of exceeding median rainfall in eastern and southern parts of the Wheatbelt,” Dr Evans said.
The department uses statistical models, which are updated monthly, to produce timely rainfall outlooks for the growing season in the south west of the state.
“The models are currently indicating that the chance of above median rainfall in May is low (less than 20 per cent), so it is likely that we could see either a late break to the 2013 growing season or low amounts in May with long periods of little rain until winter rainfall starts in June,” Dr Evans said.
“What this means for growers is that dry seeding may be a less favourable option as the risk of poor establishment from early germinated crops increases.
“Moving into the growing season, rainfall is expected to be normal to slightly drier than normal.”
Dr Evans said one of the products produced by the department was a soil water map for the wheatbelt, which would be useful in making decisions at planting.
Growers should check the SSF on a monthly basis as the season progresses and forecasting skill improves. Additionally they should use other agronomic models, soil water measurements, tools and seek advice when making decisions as the season progresses.
The SSF is a free service offered by the department via its website. As well as providing maps of rainfall forecasts for the coming months, users can click on any weather station shown in the map for more detailed, location-specific information including a graph showing rainfall to date and forecast rainfall for the rest of the season.
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