After a storm has passed clouds still linger in the sky and the thunder never stops. It will continue until I disconnect.

That might be intended, what modpack?

Your last sentence appears to be issue #18

It's my modpack. It's not intended. Issue #18 is also a problem but not what I'm talking about. The thunder will roar forever until I reconnect.

confirmed, shouldn't be thunder forever.
it never goes away

This could happen if you are near areas with lots of biomes with contrasting temperatures, IIRC thunderstorms don't count as deadly storms so they have potential to happen frequently. I'll consider closing this if I don't notice this happening in areas with more stable biome temperatures, otherwise this is an intended feature but might be worth considering a way to reduce thunder sound based on proximity to them.

well i have biomes o plenty and it never stops

Added config so you can determine how close you have to be for lightning flash and sound to play 58afd34

Also recently was testing BOP and weather2, didnt notice much issue, probably just shit luck with biome placements and constant storming, will keep these extreme conditions in mind and consider adjusting rates of thunderstorms.