Silent, disc shaped object with rotating vertical bands of light, accelerated away with amazing velocity.

It was a disc shaped craft, approximately 150 feet in diameter and about 50 feet thick. There were vertical bands of light which would rotate around the perimeter then go out, only to repeat in a few seconds. 
The object was hovering above the trees on the other side of Atlantic Street near Roseville High School, about 100 feet horizontally from us and 200 feet vertically. 
We watched it for 2 to three minutes before it accelerated away from us and up. It moved so quickly that it looked like it shrank to the apparent size of a star, but left no trail. 
You could see a discrete point of light moving vertically up until it disappeared. It made no noise that any of us could detect. 
One of my friends called the police department who informed him that they had had other reports as well from surrounding areas.
Witness indicates that date of event is approximate.  PD