Finished course in storm (7)
I believe the answer is:
overrun
'storm' is the definition.
(thesaurus)
'finished course' is the wordplay.
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'course' becomes 'run' ('run' can be a synonym of 'course'**).
'over'+'run'='OVERRUN'
'in' is the link.
(Other definitions for overrun that I've seen before include "(Programme) take too long; defeat easily" , "Go beyond schedule" , "Exceed time allowed, or spread across and injure (7)" , "Move too fast" , "UN rover (anag.)" .)