|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 six main troughs. Currently the most significant troughs are near the longitudes of South Africa, the southwest Indian Ocean, Western Australia, New Zealand, the southeast Pacific, and South America.
Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 9 April to 13 April, 23 April to 27 April, and 4 May to 8 May. Rain events originating in the tropics and moving south are possible about 7 April to 11 April, and 27 April to 1 May.
Over Western Australia the strongest cold fronts should occur about 9 April to 13 April, 23 April to 27 April, and 4 May to 8 May.
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.
14:47 EDT It has been a dry end to the summer and start of autumn in New South Wales, with many parts of the state still parched, having had little or no rain from January to March.