They're meant for static lighting users using DX8. If you have a good computer and play on DX9 or higher, you should disable static lighting weather fixes. It's an optional feature for those playing on that render.
If you play on dynamic, regular versions of the weathers should be used without the _static prefix. If SoC-style weathers look unappealing still, you can disable them in the settings.
Chocohex
joined
S.T.A.L.K.E.R. modder and translator.