Sun god in street or motorway cloudburst (9)
I believe the answer is:
rainstorm
'cloudburst' is the definition.
(I've seen this in another clue)
'sun god in street or motorway' is the wordplay.
'sun god' becomes 'ra' (Egyptian god).
'street' becomes 'st' (abbreviation).
'motorway' becomes 'M' (as in motorway names - M1, M4 etc).
'ra'+'in'+'st'+'or'+'m'='RAINSTORM'
(Other definitions for rainstorm that I've seen before include "Wild weather" , "In bad fall" , "squall" , "power shower?" , "Heavy fall" .)