From October 2022, the Bureau commenced issuing a new Heatwave Warning for severe or extreme heatwave conditions.
The Heatwave Warning service will provide a public warning that a heat hazard is forecast within the next 4 days and help Australians to prepare for and lessen the impacts of a heatwave event.
The warnings will include 5 sets of action statements agreed with our partner health and emergency service agencies across Australia.
The action statements align to the severity of the heatwave to help the community understand and prepare for heatwave situations.
The heatwave warnings issued by the Bureau will be complemented with heat health messages provided by state and territory agencies.
The Bureau will issue a heatwave warning for your weather district if a severe or extreme heatwave is expected.
Warnings will be sent to Health and Emergency Management agencies and issued through the Bureau of Meteorology website and Bureau's Weather App (BoM Weather App) and telephone service.
Heatwave warnings will be issued at 3 pm local time for all states/territories except Western Australia where it will be issued at 2 pm local time.
Heatwave warnings are issued for two types of heatwave:
Severe Heatwaves are likely to be more challenging for vulnerable people such as older people, particularly those with medical conditions.
Extreme Heatwaves are rare. They are a problem for people who don't take precautions to keep cool—even for people who are healthy. People who work or exercise outdoors are at greater risk.
The Heatwave Warning consists of 4 maps covering 4 three-day periods, extending out to 3 days in the future. The warning includes a description of the expected maximum and minimum temperatures, the timing of when the heatwave will peak and/or ease and affected towns and communities within the warning area.
The heatwave service provides heatwave assessments, which identify heatwaves in the preceding days, and heatwave forecasts, which predict those about to occur.
The maps use colour coding to show the three different heatwave intensities, so you can see what conditions are heading your way.
The yellow colour indicates the lowest level of heatwave, while the warmer colours of orange (severe) and red (extreme) indicate rising severity.
The Heatwave Assessment consists of two maps for the previous two three-day periods. Each map shows the location of heatwave conditions, and the level of intensity. The map is accompanied by text describing the conditions.
The Heatwave Forecast consists of five maps for the next five three-day periods. Each map shows areas where heatwave conditions are forecast and the intensity they are expected to reach.
Heatwaves are calculated using the forecast maximum and minimum temperatures over the next three days. This information is compared to what would be considered hot for that location, and also to the observed temperatures over the last 30 days.
This calculation considers people's ability to adapt to heat. For example, the same high temperature will be felt differently by residents in Perth compared to those in Hobart, who may not be used to the higher range of temperatures experienced in Perth.
Similarly, if there has been a period of relatively cool weather in your location, then a sharp and sustained increase in temperature, this will show up in the heatwave forecast.
This means that in any one location, temperatures that meet the criteria for a heatwave at the end of summer will generally be hotter than the temperatures that meet it at the beginning of summer.