Summer’s first big heatwave to send mercury, fire risks soaring

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.

But sweltering conditions will arrive for the western suburbs from Wednesday, with four days of 35 degrees or warmer predicted. Penrith and Richmond can expect 41 degrees on 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.)

“Coastal places will get a few sea breezes, [but] everywhere else is in a land breeze pretty much the whole time,” Mr Pippard said.

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.

Sydney reached its forecast top of 26 degrees on Monday just after 9.30 am.

Fire risks

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 Sydney, the Illawarra and the Hunter, and four other 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 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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