MVP Forcefield Pro Rainfly
MVP says this about their rainfly:
Protect your gear from the elements with the MVP Voyager Forcefield Rainfly! The Forcefield was designed for keeping your discs and equipment dry with some creative engineering for easy access. This rainfly goes on quickly and has built in magnetic strips on the front, top, and putter flaps that self-clasps, giving your discs and accessories constant protection from the wet weather. The waterproof polyester with reinforced nylon bottom will fully cover the bag, offering protection on all sides.