When you are invisible and hidden, if you cast Scorching Ray you get advantage on attack with all 3 rays?

@PhilippMordasheWhen you are invisible and hidden, if you cast Scorching Ray you get advantage on attack with all 3 rays, or only 1st? all 3 #WOTCstaff

— (((Mike Mearls))) (@mikemearls) September 25, 2016