Many years ago my neighbor was a astronomy buff. He would be out in his backyard whenever some significant event was happening in the heavens. And since his knowledge was far beyond mine, the significant events were often very cool and I got to see many of them through his telescope. Early one evening he was out watching a colorful sunset. Over the back fence he told me about the phenomenon he called "High Sky." Quite simply you have clouds and a setting sun that is blocked from a direct view by more low clouds on the horizon. This allows the sun to indirectly illuminate the other parts of the cloud cover and gives up long, colorful displays. We had one of those recently.
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