I only noticed this yesterday on the realtime page of LM.org and that was only after my brother asked me about it.
When the stations feature is turned on, most strikes show a blue streak heading from station to strike. But once in awhile, there is a green streak. From what I saw yesterday, it seems like only short distance strokes were green. But I was only seeing that from one station yesterday.
So is the color based on distance, E field vs H field, or something else?