An Australian state is being warned record high temperatures are “almost certain” after sweltering through an unseasonable hot spell.
Large swathes of Western Australia recorded blistering temperatures over the weekend north of 40C, including in the state’s Pilbara region.
Port Hedland, one of the region’s largest towns, recorded a sweltering 39.9C on Saturday, according to the Bureau of Meteorology.
Nearby, Roebourne recorded a whopping maximum temperature of 40C on Sunday, more than 10C hotter than the same time last year.
Senior meteorologist Bob Tarr said a weather system known as a ‘heat trough’ was to blame for the rise, with more hot days on the way.
“There is a heat trough over northern parts of the state and the longer that pattern goes on, the more the heat builds,” he said.
“That trough has kind of been lying there for a few days without any real change in weather patterns (...) its been allowed to build up.
“The heat is building up over the northern part of the state, and then that’ll kind of translate down the coast as we go into the next few days.”
Mr Tarr said western parts of the Pilbara will continue to heat up over the coming days, and were unlikely to cool off until at least early next week.
A cold front will push some of the weather away then, but not before temperatures are forecast to reach between 8C and 10C above average.
“It (the heat trough) is quite common to get this time of year, but it’s probably happening a bit earlier than normal,” Mr Tarr said.
“Late September is pretty early to be experiencing temperatures in the 40s. People would have hoped it would stay away longer.
“It's going to get hotter in coming months (...) It’s almost certain that it’s going to be above the historical average.”
Mr Tarr warned that the forecast was even hotter than the so-called “new normal” – an average of about 1.5C warmer than usual - due to climate change.
The forecast comes a week after BOM declared an El Nino weather event following months of speculation drier conditions were coming.
BOM Climate Manager Dr Karl Braganza said both El Nino and a positive Indian Ocean Dipole event tend to draw rain away from Australia.
“BOM’s three-month forecast for Australian rainfall and temperature have been indicating warm and dry conditions for some time,” she said.
“Based on history, it is now also more likely that warm and dry conditions will persist over eastern Australia until autumn.”
Earlier this month, Sydney reported hotter-than-normal conditions and only narrowly-missed out on a September record.
Sydney’s Observatory Hill reported a sweltering 33.8C on Wednesday, according to Weatherzone, against a record of 34C.
That weather system triggered bushfire warning on the NSW South Coast, which was largely burnt in 2019-20 bushfires.
Schools in the Broulee and Merimbula areas were shuttered last week amid a catastrophic fire warnings for the region.