Antwerp is unfortunately suffering from stormy weather (9)
I believe the answer is:
rainswept
'suffering from stormy weather' is the definition.
(suffering from rain)
'antwerp is unfortunately' is the wordplay.
'unfortunately' is an anagram indicator (a bad or unfortunate spelling).
'antwerp'+'is'='antwerpis'
'antwerpis' is an anagram of 'RAINSWEPT'.
(Other definitions for rainswept that I've seen before include "Thoroughly wet" , "Wet and stormy" , "Suffering cats and dogs" , "exposed to regular lashing" .)