EnviroMatters Magazine Spr-Sum 2024-25

8 | Environment Matters

We all have the weather forecast in our pockets with the Bureau of Meteorology ‘BOM Weather’ smartphone app.

TIPS FOR READING YOUR rain forecast

Why does the forecast keep changing? Weather forecasts cover vast areas with multiple conditions, and variables that may interact and affect one another. Forecast models are constantly being run and checked by experienced meteorologists. 24-hour rainfall forecasts are updated twice a day, so it pays to check regularly if the weather impacts your activity. Why is the severe weather warning area so big? Warnings are based on forecast districts, which are very big areas. The lead time depends on the weather situation, and can extend from an hour to 36 hours. Severe thunderstorms can be volatile and dangerous, with potential for hazards such as hail, strong winds, lightening and heavy rain that can lead to flash flooding. It’s important to take action such as seeking shelter if you receive a warning. Remember heavy rainfall in one area can lead to flash flooding downstream in areas that might not have been storm-affected.

If the icon looks rainy, it will pay to pack an umbrella… but don’t be disappointed if you don’t receive a drop! I set the app location to my suburb but I didn’t get the forecast rain? The rain may have happened in another part of the forecast area, just not over your suburb. Add to that the unpredictable nature of showers and summer storms which might suddenly drench a neighbourhood but leave other parts of the same suburb dry. Why is there such a difference in forecast rain amounts? There’s a special way to read the forecast rain amount. For example, the Saturday forecast is for 4–20mm. That’s quite a difference if you’re planning to go outdoors. The first number represents a 75 per cent chance of at least that amount. That means Saturday has a 75 per cent chance of at least 4mm. The second number has a 25 per cent chance of at least that amount, so Saturday has a 25 per cent chance of at least 20mm. But that also means there’s still a 25 per cent chance of less rainfall than 4mm, and a 25 per cent chance of more than 20mm.

Download the BOM Weather app from your app store.