Okay I have posted the idea hidden in case anyone comes across this or anyone who has replied has decided they would like to read the books. Most questions I can answer if not there is a Wikia. I have set the idea a good bit into the future so for those who know nothing about Pern or the story ignorance can be explained away.
The last pass ended two hundred years ago. Thread was not due for another four hundred years at a shorter pass. Most dragon riders for the last two hundred years have expanded to other careers. Some, along with the average person, were exploring the mental talents that people had started to emerge in the middle of the last pass. There have even been attempts to breed green dragons with bronzes or browns to little success to have more dragons for those who have the talents. Many people have been taking advantage of the AIVAS computer and moved into the south. Dragonriders claiming the parts that only dragons can get to.
About five years ago dragons started producing clutches of larger sizes like it had been recorded before a pass. This time the signs were not lost as the queens rose to mate more often. The only thing that was after checking the early warning systems around the planet showed no signs of what was coming. The red star was in its frozen orbit furthest from Rukbart (the sun) as it could be. At least that was what they had learned from AIVAS. It was not until one of the early warning satellites was taken out by a meteor. It was a meteor shower but it was not a normal one. This one had come in contact with the red star bringing with it Thread. No one was prepared. They were caught off guard since they had not really been training for thread unless they lived in weyrs of the north. And from what they could tell there was more coming.
I am open to changes if anyone has them and I am open to other plots. I have a few other ideas if needed.
Tim the Yeti