UFO Sighting in Seattle, Washington on June 5th 2015 – moved over our house heading east until it simply disappeared

I was at my computer facing a large picture window that has a panoramic view of Lake Washington. I see planes coming in from the east to the small Boeing Airport several times a day so i am aware of flight paths. Suddenly there was this object directly over our house heading east at a rapid speed, it was disc shaped with lights all round it, a very light green and white lights in 2 rows, the green being above the white lights. To the south was a small plane landing at Boeing Field, the object appeared to be flying in the same path as the plane although as i said it was over our house whereas the plane was to the south several blocks over. The object subsequently disappeared, as though it flew into clouds, but the night sky is clear. It simply disappeared. It took me several seconds to realize that i was seeing something out of the ordinary, the object was very clear and bright, the shape very distinguishable. I know this was no plane or helicopter, there is no flight path over our house, and i see enough of both planes and helicopters day and night to know the difference. I think the thing that brought me out of my confusion was the fact that there was no noise coming from the object, it flew directly over our house and the lights were so unusual in color and pattern. I chose to send this to you because i have read about your organization and i felt it needed to be reported.