Left to last, as forecast (7)
I believe the answer is:
portend
'forecast' is the definition.
(I've seen this before)
'left to last' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'to last' becomes 'end'.
'port'+'end'='PORTEND'
'as' is the link.
(Other definitions for portend that I've seen before include "forecast" , "Be a sign of something to come" , "Foreshadow" , "Betoken; presage" , "Give warning" .)