The Aurora Borealis manifests itself in a huge ring above the Earth’s Geomagnetic North Pole which is referred to as the Auroral Oval. You might expect this oval to be visible from the same altitude around the globe but because it is centred on true north rather than the geographical North Pole, this is not the case.
For example, fairly minor geomagnetic activity, let’s say Kp3 will cause the lights to appear at a latitude of around 65°N to watchers in Northern Scandinavia but in central parts of North America it will likely be visible as far south as 50°N.
The best way to illustrate this oval is to study NOAA’s incredibly useful Ovation forecasting tool. While the Kp Index is always a useful indicator of the strength of geomagnetic activity in our atmosphere, the Ovation map actually tells us if the Aurora is visible from our current position.
The Ovation map is created using real time data about solar winds and the interplanetary magnetic field to provide a 30 to 40 minute forecast as to locations from where the Aurora may be visible. The model also tells us the strength of the predicted Aurora and it is important to point out that it represents the Auroral Oval as seen from directly overhead. Standing on the Earth and looking north, the oval will be visible further south than it appears on the overhead image.
Essentially, the OVATION Aurora Forecast Model is the closest science has come to accurately predicting the appearance of the Northern Lights but it must be remembered that viewing conditions will still play a huge part. Even if the Ovation map suggests that the lights are visible from where you are, it can’t help you during daylight hours or if you are standing underneath cloud-obscured skies.
Top image credit: NASA
Aurora forecast powered by: NOAA