Somewhat windy ahead, knocking back Austrian composer (5)
I believe the answer is:
haydn
'austrian composer' is the definition.
(I've seen this before)
'somewhat windy ahead knocking back' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'knocking back' says the letters should be written backwards.
'ndyah' is hidden in the letters of 'windy ahead'.
'ndyah' written backwards gives 'HAYDN'.
(Other definitions for haydn that I've seen before include "The Seasons composer" , "Joseph -, prolific eighteenth to nineteenth century Austrian composer" , "Creation composer" , "Barman" , "Classical composer" .)