The show-makers basically confirmed at the end of the season 2 when the Flash went back in time and saved his mother from the Reverse Flash, as a result disrupting the timeline. The Flashpoint Paradox animation movie adapted comic-book series Flashpoint created by Geoff Johns and remains a fan favorite. Grant Gustin revealed the title of the first episode of season 3 on his twitter handle – “Flashpoint”. He wrote “We are definitely doing this FP thing our own way. I have read Flashpoint, I have seen the amazing animated film. This will be its own thing.”
At the MegaCon panel, Carlos Valdes was asked about his opinion on whether Barry’s attempt to save his mother from the Reverse Flash would have an impact on the timeline. He said “All I’m going to tell you is things are going to be different, way different. Not in a bad way; I think in a really exciting way, and it’s that difference that’s going to inform Barry’s trajectory throughout the season, and I think people are going to like it. I think there’s every chance of a Flashpoint paradox.” Matt Letscher (Reverse Flash/Eobard Thawne) said in an interview “Barry is starting to get unfolded in this new timeline so he is losing memories of the previous timeline”. In DC comics, Barry never becomes the Flash, Justice League is fractured as they start fighting amongst themselves, and as a result, Earth is destroyed by superheroes themselves. According to credible sources, the impact of Flashpoint will be neutralized in the first few episodes, although there will be permanent ramifications. The 8th episode will feature a mega DC 4-night crossover among CW superhero shows. The origin of the big villain will be in Supergirl which will necessitate all the superheroes to join forces and fight this greater evil.
The season 3 of Flash will start from Oct 4, Tuesdays, 8:00 p.m. on the CW network.