Near-record September temperatures could be on the horizon for parts of the country’s south east as an unusually long run of hot spring weather sets in over southern Australia.
- Large parts of south-east Australia will see temperatures between 8 and 12C warmer than average this weekend
- The heat will be particularly pronounced and prolonged for south-eastern Australia
- Meteorologists say a high-pressure system has become “blocked” off the east coast
The Bureau of Meteorology is forecasting temperatures across southern Australia to reach between eight and 12 degrees Celsius above average by the weekend.
Though it was still several days out, senior forecaster Dean Narramore said by Monday and Tuesday parts of south-eastern Australia could experience temperatures as high as 16C above their September average.
“We’re getting into the high-20s for some of the mountainous areas of Victoria and New South Wales, into the mid-30s through inland New South Wales, and parts of South Australia could even get into the high-30s,” he said.
“They’re the kind of places where random towns could be approaching near record temperatures.”
Forecasts show the warm air will set in over South Australia, Victoria, and Tasmania on Thursday, and linger through SA and inland New South Wales on Friday.
Mr Narramore said it would extend from coast to coast across Australia by the weekend, from Geraldton, in WA, to Sydney.
For south-eastern parts of the country, these conditions are expected to linger for a full week, marking an unusually prolonged stretch of warm weather, according to Mr Narramore.
“It’s very warm air for this time of year, and it’s of a very prolonged nature,” he said.
“Normally we just see a day or two of warmth, but Adelaide, Melbourne, and Sydney are looking at almost a week in the mid to high 20s and even approaching one or two days in the 30s in Sydney,” he said.
- Sydney: Saturday minimum 14C, maximum 30C, Sunday minimum 15C, maximum 30C
- Melbourne: Saturday minimum 11C, maximum 24C, Sunday minimum 12C, maximum 25C
- Canberra: Saturday minimum 7C, maximum 24C, Sunday minimum 6C, maximum 25C
- Adelaide: Saturday minimum 10C, maximum 24C, Sunday minimum 13C, maximum 29C
What’s driving it?
Mr Narramore said the warm weather was being driven by a large, strong high-pressure system that had developed over the Tasman Sea, which was dragging warm air down from the north of Australia.
But, unlike other systems which moved swiftly from west to east, he said it was also moving very slowly — blocked by a “traffic jam” of weather systems.
“We’re talking about a week for it to move from inland New South Wales out into the Tasman Sea,” he said.
“And it’s not going anywhere so the sun is just warming the land up day after day.”
He said part of the “block” had to do with the jet stream — a ribbon of strong winds in the upper layers of the atmosphere, helping run weather systems around the planet — which had become split over the south-east of Australia.
He said it meant there was no wind to help the high-pressure system move on.
Mr Narramore said fairly light winds over the south east would minimise potential fire danger during the week-long warm spell.
But for the Northern Territory, which sits at the edge of the system, it would be a different story.
“Further north, it is a bit windy on the edge of that high-pressure ridge coming across northern Australia, with those gusty easterly winds,” he said.
The bureau is forecasting extreme fire danger for the Darwin, Adelaide River, and the Barkley District until at least the end of the weekend.
It comes as a large fire continues to burn near Tennant Creek, having already burnt about 10,000 square kilometres of country.
Source: ABC News