Will you see the northern lights expected tonight?
Monday night delivered a spectacular showing of the northern lights across many parts of the UK, with sightings are far south as Dorset and Bournemouth.
Also known as the aurora borealis, the colourful, shimmering green, red and purple colours lit up the northern sky, with some stunning pictures taken.
As I wrote in my blog yesterday, another coronal mass ejection from the sun has sent more charged particles our way, with another batch expected to arrive later today and into tomorrow.
It is these charged particles – mainly electrons and protons – hurtling into earth’s upper atmosphere that cause a geomagnetic storm, leading to the potential for the northern lights to be visible.
It’s all about the Kp number
Geomagnetic storms are measured on a scale that goes from G1-G5, with G5 being the most active.
The geomagnetic storm that caused the northern lights display on Monday night was a G4, which is described as severe.
For each category from G1 to G5, there are a range of Kp numbers, which are a physical measure of geomagnetic activity. It is this Kp number that gives a good indication of how far south the northern lights may be seen – shown in the map below from NOAA.
From this map, you can see that a Kp of 7 means that the northern lights could be seen across Scotland, northern England and Northern Ireland. A Kp of 8 or more means that the chance of spotting them extends across southern parts of England and Wales too.
Will you see the northern lights tonight?
The latest forecast from the Met Office’s space weather centre expects there to be a G3 geomagnetic storm through Wednesday night into Thursday, with a chance that there could be another severe G4.
This means that there’s a good chance of the northern lights being seen across the northern half of the UK, with a lesser, but not impossible chance that they could be seen from southern parts of the UK too.
— Cormac Coyne (@CormacCoyne) June 23, 2015
The final part of the jigsaw is, of course, the weather, with a need for clear spells.
Sadly, for northern Scotland, it looks like tonight will be cloudy. However, for the rest of the UK, prospects are much better, with a window of clear spells between 9pm and 3am.
The best way to try and see the northern lights is to go outside at least half an hour after sunset, away from artificial lights and look north!
If you manage to spot them, I’d love to see your pictures. You can send them to me on Twitter – @liamdutton