In other words, he claims that the storm is not going to stop in passing and hang over them. It'll pass anyway. Am I right?The storm is moving east to west above us. The storm will move from not being over us in the east, to being over us, to being over us to the west. The storm will pass us while being above us.
The faster car will pass beside us in the other lane. The fast car is behind us, it will be beside us, then it will be in front of us.
But what did he want to say then? That the hail is not for ever? But that's obvious.
I'd expect in this case it to be:
I’m sure it will pass over soon.
Or did I misunderstand something?