Gale blows itself out to a smooth finish (6)
I believe the answer is:
legato
'smooth finish' is the definition.
'legato' can be an answer for 'smooth' (musical term). I am not certain of the 'finish' bit.
'gale blows itself out to a' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'gale' is 'lega' which is within the answer.
'to' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for legato that I've seen before include "In music, in a smooth even manner" , "Smoothly (mus.)" , "scored smoothly" , "Got ale (anag.)" , "Played smoothly" .)