The heatwave conditions gripping southern Australia have their origins in the severe weather that baked Queensland late last year.
Bureau of Meteorology regional director for South Australia John Nairn says the hot air that brought record-breaking conditions across the sunshine state had now moved south.
"People will remember the extraordinary heating cycle through the tropical coast in Queensland in November and the unusual fire behaviour they had then," he said.
"Well, that was the start of the heating cycle for Australia.
"Since then we have not had a weather event that has pushed the hot air out of the continent and it's been recirculating back and forth.
"It's basically a very large pool of air that's been building and that's not being shed."
South Australia is feeling the worst effects of the weather system this week with temperatures in some regional centres close to 50C.
Adelaide is also expected to have at least three days above 40C.
There is some relief in sight with temperatures dropping later this week as a trough moves through.
But Mr Nairn said the prevailing conditions suggested a return of very hot days in the coming weeks.
"It's high summer, so we will see a return of heatwave conditions very likely," he said.
