The BBC expert explains why you may not have seen the Northern Lights on Saturday night

A weather expert has explained why many people were left disappointed by Saturday night’s Northern Lights display – and why many may not have seen them. Writing on the BBC website, Simon King said that geomagnetic activity was up, meaning the Sun was bombarding the Earth.

He said the activity was: “Very high throughout the day on Saturday, so the aurora was overhead, but unfortunately not when the sky was dark enough to see it. There were indications that activity would not be in the extreme ‘G5’ category as it was on Friday night, but had dropped to a severe ‘G3′.’

Even at that level, experts thought there was a good chance it would be visible anywhere in the UK. He explained: “It was indeed at this level until the evening but, just as darkness fell, the geomagnetic levels dropped below the threshold, leaving many of us quite disappointed to see nothing. Activity resumed after midnight, but many of us could have given up by then.”

The sun has been very active, he said: “The numerous coronal mass ejections (CMEs) – like volcanoes – from sunspots send charged particles into space and, when aimed at Earth, give us the aurora. CMEs can have different strengths and different speeds, so they can sometimes catch up with each other and become stronger just as they hit the Earth.

“Forecasters from NOAA and the Met Office Space Weather Center are predicting the arrival of another strong CME on Sunday and Monday. Geomagnetic activity is expected to be strong to severe (G4), with a chance of increasing at times to extreme (G5).

“So for another chance to see the aurora – anywhere in the UK – you might want to keep an eye on things on Sunday evening. However, there will be more cloud – and thundery showers – across Scotland, northern England and parts of the Midlands, which could scupper any chance of seeing the aurora.”

According to the US National Oceanic and Atmospheric Administration (NOAA), the earth was hit by a G5 geomagnetic storm on Thursday. A G5 rating is considered “extreme” and the strongest level of solar storm. The cause of this storm was a “large and complex” sunspot cluster 17 times the diameter of Earth.

The last G5 storm hit Earth more than 20 years ago, in October 2003, and caused power outages in Sweden. Every 11 years, the sun’s poles reverse, causing bursts of solar activity that result in the aurora borealis. Scientists predict that the next solar maximum will occur at the end of 2024.