The temperature bounced, the wind roared, and the SES received multiple calls for help as two air masses collided over Canberra in a “unique” blast of weather that lasted just 60 minutes in the early hours of Thursday, according to a meteorologist.
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About 1am a westerly change hit the capital, just as temperatures had started to drop for the night. Winds at the airport hit 60km/h with gusts up to 75km/h, while the mercury suddenly jumped from 16 degrees at midnight to 24 degrees.
But by 2am the bluster eased off just as quickly as it arrived.
That didn’t stop the sudden blast waking a number of Canberra’s residents, and causing headaches for a handful more. The ACT State Emergency Service received eight calls for help between 1.20am and 3.30am, and then another four calls for help from 6.30am, as trees fell on houses, a car, and over powerlines in the suburbs of Gungahlin, West Belconnen and Woden.
The SES were still clearing debris and fallen trees at about 10am on Thursday.
According to meteorologist Ben Domensino from Fairfax-owned Weatherzone, it was a “unique case” of two air masses meeting in the skies over the capital at just the right time of the evening.
“Canberra was right on the barrier at 1am between a hot air mass to the west and a cooler air mass to the east, and they were just fighting it out,” he said.
“It is pretty interesting to see it that calm on either side of the change, and typically with a change you expect temperatures to drop, but this system had warm air moving behind the change.”
Temperature inversion – where surface temperatures cool and warm air rises – had started just before the westerly change arrived, and Mr Domensino said once the change swept in it re-mixed the contrasting air masses, which in turn helped strengthen the wind.
“To get strong winds like that you need a contrast of either pressure or temperature. So once that temperature did change behind the change itself, it evened out pretty quickly,” he said.
The change was associated with one of a series of cold fronts moving across Tasmania and Victoria at the moment, while a low pressure trough ahead the remnants of ex-tropical cyclone was dragging cloud from South Australia over Victoria and southern NSW.
Mr Domensino said over the next few days Canberra would enjoy some of the better weather in the country, sitting directly between a heatwave to the north and cold fronts and rainfall to the west and south.
“Actually, compared to the rest of the country, it’s looking pretty good for Canberra because there’s a good combination of missing the rain but getting some of the heat,” he said.
“Canberra’s actually looking at some pretty warm weather over the next couple of days, today and tomorrow, before ex-tropical cyclone Christine moves through the region.”
The capital is forecast to hit about 30 degrees on Thursday and Friday, before a cooler change which could bring a few isolated showers and slightly cooler conditions on Saturday. But Mr Domensino said most of the moisture associated with Christine would fall over South Australia and Victoria before it reached the capital.
The south coast also looked to enjoy relatively mild conditions, with temperatures in the mid-20s and the chance of rain, particularly as a southerly moves through sometime on Friday.
The forecast for the capital region was in stark contrast to areas to the north, where Australia's record-setting run of weather is likely to continue into the new year. Temperatures are tipped to peak just shy of 50 degrees in the coming days.
"The hot air mass that's over central parts of the country is expected to challenge quite a few records, although it's not affecting most of the capital cities," Mr Domensino said.
Instead, the central parts of Australia will bear the brunt of the hot weather. Maree and Moomba in South Australia look likely to experience a scorching 49 degrees, with Moomba closing in on its record of 49.5 degrees, and Queensland's south-west town of Birdsville is set to reach 48 degrees.
Temperatures in Alice Springs may also near its hottest ever record of 45.2, with the Bureau of Meteorology predicting the town will reach 43 degrees.
Mr Domensino warned that certain parts of Queensland could experience the longest stretch of scorching days on record, with the town of Longreach expected to have nine consecutive days in 44-46 degree heat.
"For some places, particularly western Queensland, it'll be the most intense heatwave for some parts of the state in more than 50 years," Mr Domensino said.
with Alexandra Back
