The first big heatwave of the summer will scorch inland Australia this week and reach the east coast by Thursday, sending the mercury and fire risks soaring as it goes.
According to the Bureau of Meteorology, about half of NSW will begin experiencing a low-intensity heatwave from Monday that will strengthen.
By Wednesday, more than a third of the state will have severe heatwave conditions, with a similar day forecast for Thursday.
Tibooburra in the far north west is looking at a scorching 42 degrees on Wednesday, climbing to 43 on Thursday, and back to 42 on Friday.
Bourke is sitting at just a degree below Tibooburra on all those days, while Cobar will hit 40 on Wednesday and Thursday before dropping to 39 on Friday.
Nyngan is forecast to get 39 on Wednesday, 41 on Thursday and 40 on Friday, while Forbes is due to hit its hottest temp of the week on Thursday at 40.
Moree is headed for 35 on Wednesday, 37 on Thursday and 38 on Friday, while Tamworth is headed for a top of 36 on Wednesday, 37 on Thursday and 38 on Friday.
Tenterfield is much cooler with a top of 30 not forecast til Saturday.
In the Hunter a top of 41 is due to hit Scone on Thursday, Mudgee is forecast to hit 37 on Thursday.
Further west and Broken Hill is looking at 41 on Wednesday, 35 on Thursday and 37 on Friday.
The Riverina is also looking hot with 41 at Griffith on Wednesday, 39 on Thursday and 38 on Friday, while Wagga is slightly cooler at 38 on Wednsday, 36 on Thursday and 36 on Friday.
Yass is headed for a hot 36 on Thursday, Cooma a cooler 31 on Wednesday and Thursday.
Just as a nearly stagnant weather pattern cloaked Melbourne and much of Tasmania in record-breaking heat last month, the coming week's warmth is tied to a low-pressure trough that is crawling eastwards.
"It's really slow moving," Joel Pippard, a meteorologist with Weatherzone, said.
The build-up of heat is triggering extreme heatwave conditions from Monday even in the Kimberley and Pilbara - two regions of Western Australian that are no strangers to hot weather.
By mid-week, a swathe of heat will have spread to the coast. (See chart below.)
Western Sydney needs quite a strong sea breeze to push back the north-westerlies, and most suburbs beyond Parramatta or Bankstown won't get them until late in the weekend.
"That's why we're seeing such high temperatures over such a long time," he said.
Along with the higher temperatures, fire risks can be expected to rise later in the week.
The current fire danger rating was "high" on Monday for the North Western, Northern Slopes, North Coast, Greater Hunter, Central Ranges, Sydney, and the Illawarra/Shoalhaven regions of the state, according to the Rural Fire Service.
Mr Pippard said some regions of the state can expect severe or higher fire risks by later in the week.
At this point, however, winds are expected to be only moderate when the trough moves over Sydney on Thursday, helping to temper the threat.
That change, though, will be fairly limited.
Friday's predicted top of 27 degrees on Friday for Sydney and 25 degrees for the Illawarra is followed on current forecasts by a maximum of 33 degrees - and the possibility of a thunderstorm - on Saturday, Mr Pippard said.
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