system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do scientists predict when Northern Lights will appear days or weeks in advance?
gpt
The Northern lights are produced when ionized particles from the sun get trapped in the Earth's magnetic field and sucked down into the atmosphere.

The sun is constantly emitting a low level of these particles, but it also lashes them out in violent bursts from solar flares and mass ejections.

When astronomers see the surface of the sun start generating warped magnetic fields that precede these events, we know a solar tantrum and the resulting auroral lights are imminent.