Sometimes newly spawned storms cannot be seen in the sky and on the radar. They appear after they intensified one stage or after a relog. If that new thunderstorm doesn't intensify, it stays invisible.

Some other small things:
Podzol doesn't turn into dirt
Farmland, mycelium and grass path fly away, but should be turned into dirt as well
Glass blocks and panes fly away instead of just breaking
Tall grass doesn't fly away, but in my opinion, grass and flowers should just be destroyed instead of flying away