The Earth is currently in the firing line of four distinct coronal mass ejections (CMEs), which means we could experience geomagnetic storms throughout the weekend. And while it’s unclear exactly how strong these storms will be, such events are known to trigger spectacular auroras at lower latitudes than one would typically expect to see them.

Coronal mass ejections are expulsions of plasma and magnetic fields that are fired out into space from the Sun when solar flares erupt. When the charged particles of a CME interact with the Earth’s magnetosphere, they can trigger geomagnetic storms, enhancing the strength and geographical spread of the auroras.

According to the National Oceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Center (SWPC), two CMEs associated with an M-class solar flare began their journey towards Earth on Wednesday, August 7th. The following day, an X-class solar flare erupted, hurtling a third CME in our direction.

X-class signifies the strongest category of solar flare, with Thursday’s event rated at X1.3 (on a scale of X1 to X9). 

According to the SWPC, a “faint CME” associated with another M-class flare was then detected early this morning (August 10th), bringing the total number of plasma blasts heading our way to four. Last night, the sun let off yet another CME, although this one is expected to “pass upstream of Earth orbit.”

With all four coronal mass ejections predicted to reach us between now and Monday, the SWPC has forecast periods of G2 geomagnetic storms from August 10th to 12th. Storms in this category are classified as moderate, although confidence in the magnitude of the weekend's upcoming events is described as “low”.

According to spaceweather.com, the severity of these storms could be upgraded to G3 if all four CMEs collide with the Earth in quick succession. And with sunspot activity currently high as we approach the solar maximum, the possibility of further M-class and X-class flares between now and the end of the weekend remains elevated.

There’s currently no indication of how strong the auroras associated with these storms might be or how far away from the poles they will become visible, but we do know that the Perseid meteor shower is due to peak on the night of August 11th to August 12th. If a strong geomagnetic storm happens to coincide with this spectacular annual event, then stargazers could be in for a truly unique double whammy this weekend.