So, since the TSC update, i'm getting OOM errors even before the game loads - it won't even let me in the game if I run in 64 bit. I hope i'm not the only one with this issue. It just gets to the loading screen for a split second before..... POW!
All good here - it seems in your case you need to validate your files through Steam though, and then reinstall the AP Sky & Weather EP.
Ugh - my PC has hardly any space left - looks like I might just bite the bullet and do a complete reinstall...... :/
Did you manage to clear cache? You can do that manually, the on-load culprit will be most certainly the scenario cache (SDBCache). I don't know how the game picks up enhancements but those might interfere, too. You can have a minimal installation below 2GB with removing all DLC. One by one, except one. Very fun. I could supply mine but it automatically adds (installs) all differences.
I couldn't even access the game - so I did a complete reinstall. It works now - one of my many mods probably broke something.