I was walking with my dog in a pitch dark sky - the moon hadn't "risen" yet, when, all of a sudden the sky lighted up like daylight - with a greenish hue. I looked up and there were these bright green orbs dancing around over my head (a large one and 3-4 smaller ones) - moving very quickly northward - where they disappeared above the clouds and it became dark again. It all lasted about 30 seconds... At first, I thought that it was a flare or firework; but these orbs were coordinated - the smaller ones moving around the bigger one - and they were very high - they did not disappear in the clouds, but above the clouds to the north. There was lightning in the north and these were storm clouds...