I have an SMP world on 1.7.10 with one of my friends using this mod and several others (we host it through Local Area Network via Hamachi), and the weather2 mod was working perfectly fine, and at one seemingly random point, the cloud and storm particles became invisible. Storms can still spawn, and tornadoes still affect the world, but the cloud particles do not appear at all. The other problem is the particle-based rain. It will fall when there's an invisible storm overhead, but the rain particles will freeze-frame before they hit the ground causing a cloud of glitched out rain at ground level that doesn't go away until the world is reset. Both of these are only a problem with the one specific world, as none of my other worlds have the problem.

I am running this with the Journey Map mod, but in all of my other local worlds, the weather and map work perfectly fine together.

EDIT: I accidentally activated the Chunk Boundary overlay that Not Enough Items includes, and all the weather appeared in the sky, but it goes away when I deactivate the overlay

Hmm interesting, another thread has an issue with overlay as well, but backwards to this. #73

SMP != SSP, which core server is used?