This just in...a fabulous Lauren Ralph Lauren Aztec Anorak jacket. It zips and has snaps, plus has toggles to bring waist in on the inside. Snaps at cuffs as well, and appears to be water resistent (although I would check to be sure). Marked as a Woman's M, but could be a Men's S as well. 
 
If you are looking for great western outerwear, you cannot beat anything by Ralph Lauren.