Southeastern Australia is experiencing a dramatic rise in temperatures today, with Sydney, Brisbane, and Adelaide all expected to approach the 40-degree mark.

Adelaide is set to experience a sweltering 37 degrees today, with forecasts predicting temperatures will spike to 45 degrees tomorrow. Some inland regions of South Australia might even see the mercury climb as high as 48 degrees.

Due to the extreme heat, Adelaide’s annual Australia Day celebration, The Aus Lights on the River, along with the evening fireworks display, have been canceled. Typically, this event draws about 25,000 attendees.

Brisbane is anticipating a high of 35 degrees today, which is expected to rise to 37 degrees by Australia Day.

Canberra is predicted to reach around 40 degrees this afternoon, making it potentially the hottest location in the nation today.

Fire authorities in Victoria are asking residents across the state ot heed emergency service warnings, as extreme-to-severe heatwave conditions cause bushfires in the landscape to flare.

“We have not seen severe to extreme intensity heat wave conditions like we are going to experience over the next seven days since 2009,” Emergency Management Commissioner Tim Wiebusch said.

“Take heed of the warnings, look after yourself, look after your family, those that are vulnerable.”

Emergency services were forced to issue an urgent reminder not to leave children, pets or older people unattended in vehicles after paramedics responded to 11 cases of children locked in hot cars across Melbourne and regional Victoria.

“The temperature inside a vehicle can double and become deadly within minutes,” Ambulance Victoria Director of Emergency Management Dale Armstrong said.

“It is particularly dangerous for children to be left inside vehicles, as a child’s body temperature rises three to five times faster than an adult.”

The mercury surpassed 38 degrees in Melbourne yesterday, while temperatures soared beyond 46 degrees in parts of northern Victoria.

The city is headed for a top of 43 degrees on Tuesday, while northern parts of the state could hit record-breaking highs of 48 degrees.

“If you are on the coast you will see a bit of relief coming through on Tuesday, but that does mean we are expecting some very hot days on the way,” Bureau of Meteorology’s Jonathan How said.

“Anywhere inland, unfortunately relief only comes at the end of the week, even into next weekend, so we are looking at a run of five to seven days above 40 degrees and some locations even above 45 degrees, even pushing towards 50 degrees.”

While Australians on the east coast prepare to sweat through the week, those in the west are dealing with the impact of a second tropical cyclone in a matter of weeks.

Tropical Cyclone Luana made landfall as a Category 2 system when it made landfall along the Dampier Peninsula north of Broome.

Wind gusts up to 106km/h were recorded north of Broome, in Lombadina, along with more than 100 millimetres of rain since midnight yesterday.

The storm has since weakened to a category 1 system moving inland.

Residents along the Kimberley coast should expect heavy rainfall and damaging winds over the long weekend, which is only expected to ease from Tuesday.