Break a leg in storm (4)
I believe the answer is:
gale
'storm' is the definition.
(a gale is a windy storm)
'break a leg' is the wordplay.
'break' indicates anagramming the letters.
'a'+'leg'='aleg'
'aleg' anagrammed gives 'GALE'.
'in' acts as a link.
(Other definitions for gale that I've seen before include "Force 8 wind" , "Fierce wind" , "Bille from a bladder" , "A storm of wind and rain" , "Squall" .)