Partly stormy this traditional story (4)
I believe the answer is:
myth
'traditional story' is the definition.
(I've seen this before)
'partly stormy this' is the wordplay.
'partly' indicates the answer is hidden within the clue.
'MYTH' is hidden within 'stormy this'.
(Other definitions for myth that I've seen before include "Traditional allegory" , "Unfounded belief" , "Tall tale" , "lie!" , "Fancy" .)