Tempestuous movement split a party (7)
I believe the answer is:
tornado
'tempestuous movement' is the definition.
The answer and definition can be both types of natural phenomena as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'split a party' is the wordplay.
'split' becomes 'torn' (I've seen this in another clue).
'party' becomes 'do' (do is a kind of party).
'torn'+'a'+'do'='TORNADO'
Can you help me to learn more?
(Other definitions for tornado that I've seen before include "Destructive windstorm" , "Destructive weather" , "great deal of wind" , "lot of wind" , "Tempest'" .)