| Chance of rainfall within district | |||
|---|---|---|---|
| nil < 25% |
low 25% to 50% |
med 50% to 75% |
high ≥ 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, New Zealand, the south Pacific, and South America.
Summary:
Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 14 July to 18 July, 22 July to 26 July, and 27 July to 31 July. Rain events originating in the tropics and moving south are possible about 22 July to 26 July.
Over Western Australia the strongest cold fronts should occur about 10 July to 14 July, 15 July to 19 July, and 19 July to 23 July.
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.