For LA, you should be running a 5w-40, 0w-40, or 15w-50 synthetic oil. 10w-30, especially M1 which is formulated on the thin side of 30 weight (9.8 Cst @ 100c, 30 weight is between 9.3 cst and 12.5 cst) is to thin. Note that 30 weight oils are only approved for the Big six at tempuratures below about 60F.
If you are going to use Mobil 1 (which is generally considered the best widely available synthetic), I would use one of the above forumulas. If you want to learn more than you ever wanted to know about oils, go to bobistheoilguy.com