17/11/2025
Yesterday (november 16 2025) there was a nice substorm happening around 22:00 UTC (23:00 local time here in Sweden). I did not have a chance to go out myself, but could guide a friend who was out in the field chasing and also see it all happen live on the Kiruna web camera. So I decided to make a small tutorial on what to look for and expect during a typical textbook substorm. Each picture have text explaining what's going on and what to look for or expect.
The first thing you should keep an eye on is if the equatorward (southern) edge brightens. That's a tell tale sign that something might happen fairly soon. You should also generally keep an eye on where the oval edge is in the sky. If it continuously pushes further south it indicates that something is pressing the oval to expand (i.e the solar wind). If so, the forces might well trigger some nice activity if you wait a bit.
Please note that this is by NO means a complete tutorial. Space weather and magnetosphere behavior is very complex, and a lot of things can happen that alter, halt or do other things even if you see what you see in this tutorial. And substorms can happen without these signs to. But if you see what you learn here, you should pay attention, because it's a general tell tale sign that things likely are about to go wild.
Enjoynordic nordic
