[Ref in PA]

I am a Basketball ref and a fan of football. I have always had this question in my mind and wondered how it would be called at the different levels: high school, college and pro. Here is the play.

Team A is out of timeouts and the clock is winding down toward the end of the game. Team A has the ball and throws a long pass down the middle to A1 who catches it and runs to about the 20 yard line. A1 sees he has no chance to get out of bounds and throws the ball backwards such that it goes oob around the 23 yard line. It is like he is purposely lateraling the ball to no one such that the ball goes oob. What is the ruling? Legal? Will this play stop the clock? What if A1 is in the process of being tackled (momentum still going forward) and chucks the ball oob?