Spring heatwave sweeps across southern Australia

Overall, Australia’s winter was unremarkable and despite impressions to the contrary, it was, nationally, the ninth warmest on record. The southeast had some significantly cold and wet spells and there were good examples of severe, and unusual, weather:

• Deadly floods in eastern New South Wales
• Sydney’s Bondi Beach blown inland
• Tasmania’s best ski conditions since 1992

Even before winter’s end, and the arrival of the spring equinox, a large area of high pressure has given a sudden surge in temperatures. Hot air has been drawn in on a northerly breeze from The Kimberley.

Perth hit 32C on 10 September, just two degrees off the September record. It was the earliest date on which September temperatures had reached 30C or more in 76 years.

Adelaide was the next major conurbation to feel the heat. Temperatures reached 25C on Friday and 30C on Sunday. A cold front, which brought the wind around to a westerly direction, dropped temperatures to just 15C on Monday, compared with a September average of 19C. 

Melbourne, after running a cold three to six degrees below normal for September, has just thrown off the winter coat and enjoyed a couple of days at 25C. It was business as usual on Tuesday as temperatures fell back to 16C.

As Tasmania’s Ben Lomond National Park sees the end of the 2015 ski season, Hobart, the state capital also caught the brief heatwave. Monday saw 27C posted as the day’s maximum, a full 12 degrees above average.

We are now close to the equinox, the primordial rite of spring, and although this heatwave is fading away, this year is hosting a major El Nino. This movement of Pacific Ocean warm water has worldwide weather implications, and for Australia it usually implies higher than average spring and summer temperatures throughout the south.