Half of Australia will swelter through a blistering heatwave in coming days, marking the first hot weather event of summer. The Bureau of Meteorology (BoM) issued a heatwave warning in multiple states from December 6, with Broome in northwest Western Australia and North Queensland among the first to be impacted. Conditions are expected to drift in a southeasterly direction in coming days with a heatwave warning issued for NSW and outback South Australia for the weekend. While the capital cities will be spared the worst of the heat, BoM's senior meteorologist Miriam Bradbury said areas near Sydney would feel the heat. "As the warm weather pushes over the coast on Friday and Saturday, it will start to impact Sydney, the Illawarra and Newcastle," she said. According to BoM, Sydney will hit a top of 35 degrees Celsius on Saturday before a cool change moves in over the city at the beginning of next week. Canberra is forecast to reach 36 degrees Celsius. "It's really a warning to all of us that we need to be aware of the heat and stay cool and hydrated," Ms Bradbury said. "Where possible, check on neighbours and pets." It comes after Tropical Cyclone Jasper, Australia's first of the season, is gaining steam off the coast of Queensland. Current forecasts have the system on track to become a severe tropical cyclone as it rages over the Coral Sea, but it's expected to remain well-offshore in coming days. Ms Bradbury said it was too early to be certain about the system's trajectory, including any clash with Australia's coastline. "Going into next week, it is quite possible the system will start to approach the shore," she said. "Across the weekend going into next week, it gets less certain about how it may track, but there is a possibility that it will approach the northern Queensland coast next week."