South-east states are bracing for a prolonged severe heatwave from Saturday, with potential to break all-time temperature records and fuel dangerous bushfires. Inland regions could see maximums well into the 40s for seven consecutive days, including peaks up to 48 degrees Celsius, surpassing the intensity and longevity of the early January heatwave.
Adelaide, Melbourne and Canberra are forecast to hit 40C on multiple days. The heat originates from Australia's 'heat engine' in northern inland Western Australia, where temperatures have reached close to 50C. The region produced even hotter air than normal due to sinking air from a high-pressure system, with a maximum of 49.2C at Shark Bay on Tuesday, just 1.5C off Australia's official all-time record.
The intense heat will traverse the country before stalling over south-east states until mid-to-late next week. Fire danger will climb rapidly on Saturday as hot, dry north-westerly winds gust above 60 km/h. With ongoing drought and low soil moisture, fire dangers are predicted to reach 'extreme' in more than 10 districts and 'catastrophic' on Yorke Peninsula.
A cool change will reach the SA and Victorian coastline on Saturday night but will weaken over inland areas. Temperatures will climb well above 40C again on Sunday, with north-westerly winds carrying heat to the NSW coast, including up to 40C in Western Sydney. Fire danger will lower to 'high' on Sunday due to lighter winds, though 'extreme' danger is possible in north-east Victoria.
Early next week, a renewed burst of even hotter northerly winds will send temperatures up to 17C above average, with afternoon highs up to 48C across the Murraylands, Riverland, Mallee, and lower western NSW. Adelaide and Melbourne may bounce back to low 40s on Monday or Tuesday. The extended run of well above average temperatures, including minimums near 30C, has placed a substantial inland swathe in 'severe' or 'extreme' heatwave category.
The hottest air will shift north, potentially bringing 48C to northern parts of NSW and SA from Wednesday, while southern inland Queensland could reach 47C. Numerous all-time records are in danger of being breached. The longevity of the heatwave is notable, with Mildura possibly recording seven consecutive days above 40C for the first time since 2009.
