A surge up occasionally tracks forecast (6)

I believe the answer is:

augury

'forecast' is the definition.
(thesaurus)

'a surge up occasionally tracks' is the wordplay.
'occasionally' means one should take alternating letters.
'tracks' becomes 'ry'.
'surge'+'up'='surgeup'
The alternate letters of 'surgeup' are 'ugu'.
'a'+'ugu'+'ry'='AUGURY'

(Other definitions for augury that I've seen before include "Portent or prophecy" , "Prophesy" , "Omen or its interpretation" , "Sign or omen" , "Divination, prediction" .)

I've seen this clue in The Telegraph.

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