Temperatures across southeast Australia are set to soar for at least the next four days, with some areas reaching 45 degrees.
Heat building over western NSW will push towards the coast over the weekend and early next week, forcing temperatures up to 16 degrees above average.
As a result, fire danger will be elevated on Sunday and Monday, with the RFS warning people should use the next few days to prepare.
"People need to take this seriously... this season we haven't had these heightened fire dangers but we have now got to be prepared," RFS NSW director Peter McKechnie told reporters on Thursday.
Bega, on the south coast, is expected to reach at least 39 degrees on Monday, and western Sydney will be in the same range on Sunday and Monday.
Other parts of southern NSW could experience temperatures up to 45 degrees on Sunday and Monday, according to the Bureau of Meteorology.
NSW has copped a lot of rain over the past few months, but fuels are still quite dry in the state's south and west, meteorologist Gabrielle Woodhouse says.
Victoria will also see temperatures building to a peak on Monday, with most major centres in the state's north surpassing 40 degrees. NSW-Victoria border towns could endure temperatures up to 44 degrees.
A significant #heatwave will impact #SA, #Vic, #NSW and #ACT as temps soar over the weekend and into the #AustraliaDay public holiday.
Make sure you keep cool and stay hydrated – and don't forget your pets! 🐶🐱
Latest forecasts: https://t.co/qDSm8yAGi4 or the #BOMWeather app pic.twitter.com/rzRiUtQSZX
— Bureau of Meteorology, Australia (@BOM_au) January 21, 2021
A cool change is due to hit the state's southwest on Monday but won't reach the northeast before early Tuesday morning.
Victorians could find themselves sweating through the night on Sunday and Monday as temperatures stay high even after the sun sets.
BoM expecting ‘scorching heatwave conditions’
BOM meteorologist Jonathan How said conditions over the weekend in southeast Australia would be the warmest since January 2020.
He said relief would not arrive for at least four days.
The @BOM_au has forecast a heat wave to affect parts of #NSW later this week. This is likely to increase fire dangers especially in western parts of the state. Use the next few days to plan and prepare. Know what you will do if threatened by fire. #NSWRFS https://t.co/VeGOFqDj9g pic.twitter.com/x6RrHVYcs8
— NSW RFS (@NSWRFS) January 18, 2021
"Summer is really back in full across southeast Australia ... 15 million Australians will experience the scorching heatwave conditions over the next few days," Mr How told the Nine Network on Friday.
The heatwave has lifesavers on high alert, with Surf Life Saving NSW CEO Steven Pearce saying this is "probably the weekend we've been looking out for".
The heat is likely to drive people to the beach and a large swell will pose some "real challenges" for lifesavers and life guards, Mr Pearce told reporters. More than 1000 people have required rescuing since Christmas Day.
A severe to extreme heatwave is already besetting southwest Western Australia and western South Australia. A low intensity heatwave is expected to persist in SA until next week.
WA braces for cyclone
Western Australia's Pilbara and Kimberley regions are bracing for a tropical cyclone to be called Lucas, with communities being urged to prepare themselves and tourists told to evacuate.
The Department of Fire and Emergency Services has issued a Blue alert for communities between Beagle Bay and Port Hedland, including popular travel hotspot Broome.
"People... need to prepare for cyclonic weather and organise an emergency kit including first aid kit, torch, portable radio, spare batteries, food and water," the alert issued on Friday morning reads.
Did you know that tropical cyclones can influence heatwaves? We had a chat to Dr Tess Parker about how the #tropicalcyclone forming near northwestern Australia is going to influence the impending #heatwave in southeastern Australia.
Full story > https://t.co/ots3lGzu8h pic.twitter.com/8mnR1UO7YK
— Weatherzone (@weatherzone) January 21, 2021
The Bureau of Meteorology said a tropical low was intensifying as it moved towards the coast and and may develop into a cyclone early on Friday and reach category 2 intensity later in the day.
Gales may develop on the coast near Bidyadanga and Broome during Friday afternoon and may extend to other parts of the warning area during Friday evening. But gales are not likely at Port Hedland, the bureau said.
"Heavy rainfall combined with strong winds may develop along the west Kimberley coast and east Pilbara coast, to the east of Port Hedland, early on Friday and extend inland east of Port Hedland during Friday afternoon and evening," the BOM said.
— Bureau of Meteorology, Western Australia (@BOM_WA) January 21, 2021
Holidaymakers camping or travelling in caravans are being urged to find safe accommodation or leave the warning area immediately.
"A cyclone is not a place you would want to be in a caravan or camping," DFES assistant commissioner Paul Ryan said.
"It's probably going to take you a couple of days but we need to start planning and moving now."
The Bureau of Meteorology had anticipated a potential category three cyclone but has downgraded its forecast.
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