’Major flood and rain event’ about to hit
Australia's "heat engine" is set to essentially shut down, at least for a time, bringing an end to the scorching temperatures that have plagued the continent.
Forecasters have warned of a "major flood and rain event" for the east and northwest of the country.
Sydney hit 40C late last month while Perth's CBD got within a whisker of the same on Tuesday.
"Australia just went through its hottest November on record but that's all over now; the heatwave is finally done," Sky News Weather senior meteorologist Tom Saunders said on Wednesday.
"Replacing it we have a monsoon trough off the northwest coast."
HEAT ENGINE SWAMPED BY CLOUD, RAIN
The absence of the monsoon, and resulting lack of moisture which can help bring the mercury down, was one of the reasons much of Australia sweltered through November. That's despite the La Nina climate driver having kicked in which should have aided in wetter and cooler summer weather conditions.
A climate scientist told news.com.au this week Australia's November weather was "crazy" and they were "blown away" by how hot it was.
But better late than never, it seems some of that much needed precipitation is finally making an appearance with one tropical low having crossed over the Pilbara and another approaching the Western Australia coast.
The pair of tropical lows are unlikely to form into cyclones but they will bring heavy rain across the Pilbara and Kimberley regions. Up to 100mm of rain can be expected in north west WA with some areas picking up 200mm and some interior rivers at risk of flash flooding.
"All the cloud cover associated with these tropical lows has dropped the temperature the northwest of the country, and we call that area the heat engine of Australia," said Mr Saunders.
"So even if we do see a northerly air stream (which funnels that air towards) southern Australia, it won't be as hot as the northerly has been over the last few weeks."
MAJOR RAIN, FLOOD EVENT
The colder air from the interior will edge its way eastwards over the coming days meeting up with moist La Nina fuelled air in the Coral and Tasman seas. An area of high pressure sitting in the Tasman will then merge all this moisture together and send it right back to eastern Australia.
"We're looking at a major rain and flood event on the east coast from about Friday onwards," Mr Saunders said.
North eastern New South Wales and south east Queensland are ground zero for the wet weather with 100mm, even 150mm, potentially coming down over the weekend.
"So it is going to be a very wet week across the country, with flash flooding and river flooding all possible, but a drier week in Victoria and South Australia," he said,
Sydney will be on the southern cusp of the rain so may not see the full effects. Nonetheless expect showers every day from Friday onwards with as much as 20mm falling on Monday of next week.
A high of 27C on Thursday but the maximum temperatures will drop down to the mid-twenties going forward.
Heading north it will be much more soggy with Coffs Harbour possibly seeing a storm on Thursday, between 10 and 30mm of rain on Friday and even as much as 70mm on both Sunday and Monday. That's well within flash flood territory.
Two tropical lows in waters north west of WA are expected to bring heavy rain and squally winds to the Kimberley and Pilbara this week. The first system is unlikely to develop into a tropical cyclone. The second is only a low risk. Check warnings here: https://t.co/XXXTUPt3Be pic.twitter.com/QJtmGOQaO0— Bureau of Meteorology, Western Australia (@BOM_WA) December 7, 2020
Very wet for Brisbane too with up to 20mm coming down on Saturday and 45mm on Sunday and more rain on Monday. Temperatures will top out in the high twenties for the remainder of the week, skimming 30C at times.
Across the Top End, a dry few days until Friday and then storms and showers will pass through Darwin each day delivering a good soaking.
Unending storms in Broome with a possibility with some heavy dumping of rains on Thursday and Friday, which could see up to around 40mm in the gauge.
Perth will continue to see a few more blisteringly hot days after Tuesday's near-40C top. Expect highs in the high 30s but with a possible storm on Thursday. Generally drier and more mild on the weekend with maximums in the mid twenties.
Sunny in Adelaide and getting warmer. The 27C high on Wednesday will reach 35C by Sunday.
Pleasant conditions in Melbourne with 25C on Wednesday, then a dip to 18C on Thursday before rising to almost 30C on Sunday. A possible light shower on Thursday.
A few passing showers in Tasmania on Thursday giving way to a sunny weekend. Hobart could reach 27C on Sunday and push beyond 30C on Monday.
Finally Canberra, and the capital could see showers on Thursday with a high of 27C. Then the mercury will drop into the late twenties during a cloudy weekend.
Originally published as 'Major flood and rain event' about to hit