28 Day Rainfall Forecast
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Southwest Rain Forecast
Southwest 28-day Rainfall ForecastSun Mon Tue Wed Thu Fri Sat 23Low4Low56789101112131415Low1617Low18Med19Med20Med21Low2223242526272829Low30LowCHANCE OF RAINFALL WITHIN DISTRICTNil< 25%Low25 - 50%Medium50 - 75%High≥ 75%Issue Notes
Issued 2 Dec 2020The hemispheric long wave pattern has been relatively fast moving in recent weeks. There are four main troughs. Currently the most significant troughs are near the longitudes of the southwest Indian Ocean, the Indian Ocean, eastern Australia, New Zealand, the south Pacific, and the southeast Pacific.
Summary:
Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 15 December to 19 December, 23 December to 27 December, and 3 January to 7 January. Rain events originating in the tropics and moving south are possible about 11 December to 15 December, 19 December to 23 December, and 25 December to 29 December. Over Western Australia the strongest cold fronts should occur about 18 December to 22 December, 23 December to 27 December, and 3 January to 7 January.
Forecast ExplanationThis 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.
