Putting new shingles over old ones is never a good idea - especially since you're in a windy area.Some manufacturers also void their warranty if the shingles are installed over old ones. Shingles rated for high wind areas should help. You may also be better off with "organic" shingles rather than fiberglass ones, assuming this is what you have. Fiberglass has a greater tendency to break rather than flex, especially in cold weather. The tabs of shingles are not intended to stick; the cement is in a line just above the slots between tabs. This is where they are nailed.

"The roof sheathing feels like 1/2" plywood and is a little wavy in places"

If severe enough, that's causing areas of the shingles to get "pockets" allowing winds to get up underneath and roll them up and off. If you insist on recovering over the old, put a barrier of 30# saturated felt between the two as the existing shingles will draw the oils out from the new shingles if not felted. As stated above, the best route to take would be to pull the existing, skin over with another layer of sheathing, and shingle away. Dimensional/architectual shingles do better than standard 3-tab shingles in high wind areas. Doing it right will be better for re-sale or for whoever gets your home when you are done with it. Pay more now or pay worse later.