Supplies cut short by supporter for time being (13)

I believe the answer is:

provisionally

'for time being' is the definition.

'supplies cut short by supporter' is the wordplay.
'supplies' becomes 'provision'.
'cut short by supporter' becomes 'ally' (I can't explain this - if you can you should believe this answer much more).
'provision'+'ally'='PROVISIONALLY'

I've seen this clue in The Times.

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