Luke 21:25-26 New International Version (NIV)
25 “There will be signs in the sun, moon and stars. On the earth, nations will be in anguish and perplexity at the roaring and tossing of the sea. 26 People will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken. ~ https://www.biblegateway.com/passage/?search=Luke%2021:25-26

People are passing this around.
The Great American Eclipse was on August 21st and Hurricane Harvey made landfall around August 25-26th. So, they want to find something to correspond with those dates. It looks like they found something in the Bible New Testament book of Luke.
The first question is, Why would they be looking in Luke chapter 21?
Well, the subtitle for Luke 21 is: The Destruction of the Temple and Signs of the End Times .
I would say, that's a pretty good place to start when you want to talk about End Times. The Book of Revelation is usually the first stop for doomsday finders, but it isn't the only place in the Bible to look.
When Luke recorded this chapter, it was probably just a regular day for the disciples, until Jesus decided to lay down some truth on them. A few of them had made a comment about how beautiful the temple was and then Jesus brought them down to earth by telling them it would be destroyed and all sorts of bad things. You can read the full NIV version of Chapter 21 here.
If you read The Event : Time Line for 2017 and The Eclipse and the Virgin of the Apocalypse, you know that this time of year is a bit special in religious circles.
Obviously, when the New Testament was written down, they didn't add chapter numbers and verses to them. But, if you believe that God had his hand in creating the Bible, you would believe that the numbering is there for a reason. And if you could just decipher the code, you could get more insight into what God has planned.
Just like the person trying to decipher crop circles, which I turned into the The Event : September 11, 2017 Mass Attacks Predicted from Crop Circle article, with a follow up article that helped bolster the theory called The Event : Next Major North Korea Missile Launch on September 11/12th. These articles were based on things that other people said and their believes of what they interpreted. I really don't want to be right on it, but what if I was and you were given a week or more to prepare?
Just like with Irma, people have been given a week to prepare. And since Harvey caused so much problem, people might be more cautious with Irma.
I'm not sure how you would prepare for an event described in Luke 21. I guess, being prepared for any sort of large disaster and civil unrest would help you prepare for Armageddon. Anyway, it is an interesting connection that people are making, not as exciting as the crop circles, but it has some zing to it.