GO FLAMES GO!
Awesome! I got clouds working, took basically three days to get them coded and all integrated into umake. They can still be improved but for now it's fine. I decided to do clouds instead of rain/snow because they were simply more difficult. I re-read the gamasutra article and indeed get some great ideas, however in the end the system I implemented was quite a bit different. Probably not as good in terms of realism, but then, their realism was largely based on giving artists good control. The core algorithm isn't much different: clouds form and dissipate, are lighted somewhat nicely by differing daylight conditions, and have a natural shading to them as well. They come in all shapes and sizes. I don't have to do any special fog code, basically the clouds can look like mist depending on the altitude of them, so I'm putting a checkmark beside that one too!
So today and tommorow I implement rain and snow. It's raining outside so I have lots of inspiration. I hope the idea that I have for rain works out, I can't why not frankly, and snow as well is quite simple. I will use the rain engine to model particles in space, and the snow engine will be used also to render fluff as well as snow. Should be nice, all-in-all, and both of these are fairly simple to do.
I won't implement lightning/tornadoes/meteor showers for the upcoming alpha. Once I have weather done I want to look at fleshing out some more story elements, or whatnot.