I've created a Nevada Skies Addon for TTW, find it at my Nexus Download Page.
I just recently started to play TTW, so I can't tell 100% if everything works as supposed, as it has been a long time since I played Fallout 3. If you find any weird weather bugs belonging to TTW please let me know here.
Please put it very late in your load order, or there is a high chance, that it will not work.
Citadel Fix for Nskies is in this post. --TJ