Updated 24 June 2015
The Space Weather team at the Met Office has been keeping a close eye on solar activity over recent days. A large solar storm resulted in the northern lights being seen as far south as Dorset and Bournemouth on Monday night.
A particularly active sunspot came into view during the early part of last week. This sunspot continued to grow in complexity which has resulted in a number of moderate solar flares and coronal mass ejections (CMEs) which is when the Sun ejects some of its atmosphere out into space. This can be seen on the image below as a faint circle, almost like smoke. These travel at speeds of around 2 million mph. On Sunday one such CME was launched directly at Earth. Travelling at these speeds it still took almost two days to travel the 93 million miles from the Sun to Earth. When it hit Earths magnetic field it caused a Severe Geomagnetic Storm (A G4 storm on a scale of 1 to 5). It was this which caused the Aurora to appear in the skies of southern England on Monday night.
Large geomagnetic storms can result in disruption to power grids, which is why it is important that these storms are monitored and warned for, although fortunately the UK grid is more resilient to space weather than the grids in many other countries. There are no impacts on human health as a result of these solar storms, in fact they can have some very welcome effects in the form of increased aurora, both in effect and extent.
Our Space Weather advisors are now watching another CME, which looks like it could be heading our way. This has the potential to bring another night of spectacular aurora views on Wednesday night. To see the northern lights, wait until at least half an hour after sunset, go outside away from artificial lights, let your eyes accustom to the dark and look towards the north. There will be some cloud around tonight, check out our cloud cover forecast for more information.