Sounds like it needs realignment, and to make sure the thing is secure. If it's dropping out that much then that dish is either really really loose.... would have to be to move it that much to cause the 99 or 103 to bottom out.
My point earlier about beam-width, let me clarify a little. I didn't mean the actual width of the spot-beam itself, I meant width in terms of a sine wave. The 101, which is our main orbital satellite in the fleet has a much wider signal-beam wave (for lack of a better term, think of it as a sine wave) width than the 99 or 103. That is why it is absolutely critical to use the dithering knobs on the Ka/Ku when tuning it in as it needs to be nearly dead-on. You could have an 80% signal on the 101/119 and have no problems with any channel being transmitted via the 101/119, but your 99 and 103 would have already dropped out or be close to dropping out. What the dithers do is fine tune the 101 and the 119 into the apex of that beam curve. With those two sat's at the apex, the 99 and 103 should also be at their apex. One degree off is like a 60 mile difference when your trying to hit a target that is 200+ miles up in low-earth geosynch orbit.
Think of it like this: Two mountains standing next to each other, both the exact same height. One has a fat, broad base and broad summit, the other has a narrow skinny base and summit. If two people stood on both summits, and started walking at the same speed down the mountain, the person on the skinny mountain would hit bottom way before the other guy ever really got off the summit. Just like a sine wave. Hope that clarifies the point I was making, I was kind of vague earlier, my bad.
In a nutshell if the dish is properly tuned, AND is securely mounted with monopoles ( I usually use 6 lags on the mast foot and 3 each on two monopoles, haven't had a SC for tuning yet I'm proud to say ^^) then you should NEVER lose signal due to wind unless the wind rips the entire thing off your house.