First, welcome to New England Team Challenge ... the best, toughest, most dedicated winter disc golf league in the nation. Speaking as the captain of the A Pool champs (Team Cran), if you (or your captain) have any questions regarding strategy, send me a pm here or on facebook ... I'm more than willing to share some basic ideas.
Second, as a 13 year vet of winter disc, my standard attire is usually a medium weight thermal poly/synthetic layer, a t-shirt or collared shirt, and medium-weight but thin and mobile jacket. If it's super cold, I'll add a long-sleeve t-shirt under the jacket and/or an outer vest over the jacket. Never liked hoodies because they add air resistance and drag with their bulk.
Did a lot of window shopping at REI, EMS, and other similar stores this past spring after busting the zipper on my favorite jacket. Then I went to a local Golfsmith to see what they have. Ended up purchasing this jacket on line for the coming season:
http://www.golfsmith.com/product/30154325/zero-restriction-men-s-highland-jacket
Tons of mobility in the shoulders (which is the company's intent), warm interior and waterproof exterior. Haven't had the chance to wear it yet, but totally satisfied with it. I've found that spring/fall season jackets with proper layering work the best as they aren't nearly as bulky as hoodies or winter jackets.