Is there any way to know or to discuss how the US markets will open based on the news and predictions?

Hi! You all know that when markets open they are always somewhat unstable and often rise or fall sharply; there are enormous variations in the first few minutes of the markets (I'm referring to the US markets, which are the only ones that interest me). For example, today the markets started the day falling immensely, most likely due to the shutdown. I didn't know about the shutdown because I'm not American, but if I had known, I could have anticipated the abrupt variation the market experienced at the opening. Is there a way to know, with some certainty, what will happen when the US markets open? Is there somewhere we can discuss the behavior of the markets each day as they open? Thank you very much. Best regards.