The aurora australis could be visible from large areas of Australia on Wednesday night into Thursday morning as a severe geomagnetic storm disrupts Earth’s magnetic field.

The Bureau of Meteorology’s Space Weather Service (SWS)issued an ‘aurora alert’ on Wednesday afternoon, an advisory that only gets issued when space weather activity that is favourable for viewing aurora is currently in progress.

The aurora alert stated:

“Severe geomagnetic storm in progress. Aurora may be observed during local nighttime hours in good observing conditions at regions as far equatorward as middle latitudes.”

The geomagnetic storm that is expected to cause Wednesday night’s aurora australis was caused by a coronal mass ejection (CME) from the Sun earlier this week.

While it’s difficult to anticipate the impact a CME will have on Earth ahead of time, the influence of this event has already started to occur, and it is causing a severe geomagnetic storm.

Image: Aurora australis seen from Inverloch, Vic in 2024. Source: @tompasco / Instagram.

The strength of a geomagnetic storm is measured using the G-scale, which goes from G1 to G5, with G5 being the strongest level on the scale. According to the Bureau’s SWS, a G4 storm was underway on Wednesday afternoon and conditions could reach G5 strength on Wednesday night.

G4 geomagnetic storms are capable of causing the aurora to become visible in central NSW. The SWS says that under G4 conditions, “bright auroras will be visible at unusually low latitudes, including dark-sky locations near Sydney and Perth.”

If G5 conditions occur on Wednesday night or Thursday morning, the aurora could even become visible in parts of Qld and the NT.

Fortunately for Australian aurora hunters, a high pressure system will keep skies clear over large parts of the country on Wednesday night.

You can find more information about space weather and the aurora australis on the Bureau’s SWS website.