Stopping fixed position scrolling at a certain point?

I have an element that is position:fixed and so scrolls with the page how i want it to however. when the user scrolls up I want the element to stop scrolling at a certain point, say when it is 250px from the top of the page, is this possible? Any help or advice would be helpful thanks!

I had a feeling that I would need to use jquery to do so. I tried getting the scrolling or location of the where the user is but got really confused, is there any jquery solutions?