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The wording is careful, and contains no guarantees, but veteran aurora australis hunter Margaret Sonneman says what the BOM won't just yet — things are looking good for a cosmic light show worth staying up for.
The BOM's Australian Space Weather Forecasting Centre alert, posted on Wednesday, states a "coronal mass ejection is expected to impact the Earth" around midnight Australian Eastern Standard Time on Thursday, give or take 10 hours either side, "possibly resulting in significant geomagnetic activity and visible auroras".
Even with the caveat of "possibly", this stuff is cosmic music to the ears of aurora enthusiasts, of which 232,960 follow Ms Sonneman's Facebook group Aurora Australis Tasmania.
The page, which showcases the aurora australis — Latin for "the southern dawn" — features photos and time lapse videos of the astonishing curtains of multi-coloured light, with the occasional meteor or bioluminescence thrown in as a bonus.
It is also a place for the exchange of information on whether it is "on" for aurora chasers, who are known for venturing into the night in the hope of the perfect shot.
Ms Sonneman, who created the Facebook page 12 years ago, is careful what she posts these days about the chances of the lights showing up.
One time, when things were looking very promising for aurora activity, "people flew in to Tasmania from interstate, I was doing interviews all over the place … and nothing happened," she laughed.
NASA explains coronal mass ejections (CMEs) as "huge bubbles of coronal plasma threaded by intense magnetic field lines that are ejected from the sun over the course of several hours" which "often look like huge, twisted rope, which scientists call flux rope".
This can result in spectacular displays, known as aurora borealis in the northern hemisphere and aurora australis in the south, but whether the activity on the sun happens in just the right way to cause the lights to be visible on earth is difficult to predict.
"I have been saying I think something is coming," Ms Sonneman said on Thursday afternoon.
She said there had been "significant" activity on the surface of the sun over the past few weeks — but what that meant for people with phones and camera on tripods over 147 million kilometres away on earth was unclear.
Around 8 o'clock, during this time of the year, Ms Sonneman posts on the Aurora Australis page how things are looking for the coming hours.
"I don't really venture an opinion … but we could be getting something," she said on Thursday afternoon.
In a statement, a BOM spokesperson said the current forecast was for a "minor level geomagnetic storm", during the overnight in Australia.
"If the storm progresses as forecast, then there will be a good chance of visible aurora from the southern areas of Australia, such as Tasmania."
The BOM said the event was "not expected to be as strong as the events in early November and December from last year but is expected to be about as strong as some events which occurred in the middle of those two months".
The BOM's Dr Jeanne Young advised aurora chasers to look for a "dark beach or a hill where you have an unobstructed view to the south".
"Bright auroras usually last for 1–3 hours and the best viewing time is around midnight — between 10pm and 2am. However, there's no magic hour that you're guaranteed to see auroras.
"Keen aurora chasers usually keep an eye on our real-time geomagnetic indices which show the level of geomagnetic activity and stay up all night if need be!"
With a full moon early morning on Friday, aurora chaser Chris Blakaby says he is doubtful of getting good shot, but would still "monitor" the situation.
"Aurora has to be really strong to beat moonlight, once at 89 per cent (full moon) last year we all managed to capture an aurora," he said.
Ms Sonneman said if the "aurora is bright enough, you've got the landscape illuminated by the moon, so I do not discourage people from going out on a full moon".
And while venturing to a high point, such as kunanyi/Mount Wellington, to increase the chances of a cloudless shot, Ms Sonneman urged people to persevere and "look for cloud gaps".
With the space weather forecasting, as well as cloud cover technology, assisting those keen for a photo or video of the southern lights, it still is a case of doing the hard bit of stying up late and waiting — with no guarantee.
Ms Sonneman said she would be one of the undeterred out overnight.
"I know what it's like to sit up all night and nothing happens."
People keen to witness an aurora can subscribe to the BOM's alert system.
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