Hi. I've been having this problem with my video in Skyrim for a few weeks now, where there are these weird and startling graphical artifacts appearing on my screen. They appear at random, except they seem to only happen at night or in the late evening. What happens is that, when I look in a certain direction, the horizon is filled with this huge multicolored shapeless blob, which flashes rapidly while I walk or turn my view. When this is happening, the grass is also flickering rapidly. I thought at first that it was my cards overheating, but when I made my fan speed curve more aggressive, it didn't help the problem. Also, I don't get anything like this in other games.

Sometimes the artifacts look like the "missing mesh" exclamation point models (can't tell for sure), but exploded in all directions. I wonder if there's some messed-up object of some kind in a certain area in the game world, which is causing this when I look at it? I guess it would have to be something that's visible when distant and near the world's center, if that's the case.

MSI Big Bang Xpower II motherboard
Intel Core i7-3820 (3.6-3.8 GHz)
8 GB RAM (DDR3 1600)
2 x Nvidia GeForce GTX 570
3 monitors with Nvidia Surround, combined resolution 3860x1920

Video cards usually reach 50-60 degrees Celsius in 3D games; I've heard this is pretty normal and that my card model has good cooling (they're not overclocked other than factory OC)

Nvidia drivers version 301.42
Ultra settings, except:
MSAA disabled
FXAA enabled

What are the thermal readings from your monitor program recording at those times?

I've noticed the same thing several times. Exiting and reloading has always fixed it. I've heard that sometimes the scene doesn't load correctly for some reason. It should be fairly rare (it's happened to me 3 times total) so if it's very frequent, there may be something else going on.

edit: the change of AoT effect on fire spells is much more important but even there, it's probably a good idea. IMHO it just encouraged spamming muffle to get to 50 skill ASAP.