It depends how fast you'd be able to travel... it doesn't look like something like this will last for months, but within the month, maybe. It'll take a while for all the froth to go away, but it might not look as cool weeks from now. However, Sydney is a really awesome city and Australia is an incredible place to visit. Even if you're just able to catch a little bit if a glimpse of the froth left, seeing everything else there would be more than worth the trip.