A bitter blow is wanted badly (4,4)
I believe the answer is:
east wind
'a bitter blow' is the definition.
The answer and definition can be both types of natural phenomena as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'is wanted badly' is the wordplay.
'badly' indicates anagramming the letters (letters in the wrong order).
'is'+'wanted'='iswanted'
'iswanted' anagrammed gives 'EAST WIND'.
Can you help me to learn more?
(Another definition for east wind that I've seen is " Chilly air current".)