How is a weather forecast made?

Weather forecasts are prepared by meteorologists who look at all available data and information and use their experience and training to come up with the best estimate of what the weather is going to do in the future. There are two main forecasts on the website. The first of these is the temperature and précis forecasts that you see on Your Local Weather page or on the State based pages. These will be prepared by looking at the available computer models and deciding which of these models (there may be more than one) is the favoured scenario.

The forecaster then uses their experience to interpret this model to come up with a maximum and minimum temperature. Factors which go into maximum temperature forecasts include the temperature of the upper atmosphere, any cloud cover and any rainfall. Factors which go into minimum temperature forecasts include the temperature of the previous day, any cloud cover, wind and humidity level.

Precis forecasts are derived by looking at the model?s predicted rainfall and moisture parameters. These are then interpreted by the forecaster and amended if needed.

The second main type of forecast on the website is the rainfall forecast charts. These are also prepared using computer models. At the beginning of the day, the forecaster will look at all the available models and work out which has been performing the best over recent days and which they are going to use as their basis to work from for the day.

Once this has been decided upon, all forecasts prepared by forecasters during that day will be based off that same model, ensuring consistency across the website. The rainfall prognosis of the favoured model is then altered as necessary to create the rainfall forecast charts on the website.

• 08:00 AEST A digger's letter from snowbound Gallipoli
• 15:39 AEST Summery Sydney, wintry Melbourne
• 13:00 AEST Rainfall to soak some parched areas of WA
• 10:33 AEST Tassie snow, Melbourne temps go low