|Chance of rainfall within district|
25% to 50%
50% to 75%
The hemispheric long wave pattern has been relatively fast moving in recent weeks. There are five main troughs. Currently the most significant troughs are near the longitudes of South Africa, the Indian Ocean, Western Australia, the south Pacific, and South America.
Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 4 October to 8 October, 19 October to 23 October, and 30 October to 3 November. Rain events originating in the tropics and moving south are possible about 1 October to 5 October, 7 October to 11 October, and 11 October to 15 October.
Over Western Australia the strongest cold fronts should occur about 1 October to 5 October, 10 October to 14 October, and 19 October to 23 October.
This forecast is produced by a multi-model ensemble consisting of dynamical atmospheric models, which are forced by the latest observed atmosphere, ocean, land and ice conditions. The models are designed to simulate features of the real atmosphere, including the daily movement of long and short wave patterns in the Southern Hemisphere.
The future probability of rain in each district is estimated using output from the multi-model ensemble, combined with historical information about the difference between the model forecasts and observed rainfall.
In this deterministic framework the skill of the forecast tends to decrease with time, however the forecasts are updated daily to provide the latest estimates of rainfall probability out to 28 days.
15:18 AEST A low pressure system is generating a series of cold fronts that are likely to affect WA later this week.