As far as I can remember, this has not happened before...

http://postimage.org/image/ouwv9m71z/

What could possibly be causing it?

I am only using All Natural (the latest version), for sky textures and so on. Everything is up to date, patched, cleaned, etc.

One of the two moons over Tamriel is starting an invasion.

(no serious guess here sorry)

Set the texture size (or whatever it's called) to large in Oblivion's settings.

That's always one of the first things I do. It's set at Large already.

Can you use the debug ring available on All Natural's Nexus page to get the weather ID for me then?

Oh, silly me - I forgot all about that!

Weather Debug Ring - Current Weather: 010186E8 TargetWeather: 010186E8 OldTargetWeather: 00000000 Percentage: 1.00 Cell: 1 CurrentTime: 32.62 TimeForCheck: 34.92 Region FormIDs:** Dumping Array #2 **Refs: 1 Owner E7: Weather Debug Ring.esp[ 0.000000 ] :  (00053728)[ 1.000000 ] :  (0014C7DC)[ 2.000000 ] :  (0006EF2F)

Did I get all the right bits from the Conscribe log?

That's fine, thanks. I'll take a look at the textures used by that weather when I get time to.

If it helps at all, so far the other weathers are fine (I had my character wait around a couple of times, regardless of being hassled by random conjurers, haha).