2006 Hyundai Tiburon Vibration

When driving down the highway, my car has started vibrating pretty strongly. It feels to be vibrating most on the passenger side front area. It only vibrates when the speed is 60 mph or over. I have brand new tires on my car and checked to see if it needed air, but they are fine. We recently got the alignment fixed, and it is still driving straight. What would cause it to vibrate so hard when accelerating over 60 mph and is seeming to come from the passenger side front fender area?