Observe the stormy surge and foam (6)
I believe the answer is:
seethe
'foam' is the definition.
(synonyms)
'observe the' is the wordplay.
'observe' becomes 'see' (observe can mean to see something).
'see'+'the'='SEETHE'
'stormy surge and' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for seethe that I've seen before include "Feel intense rage" , "Appear as if boiling" , "Boil, be turbulent" , "Smoulder" , "Bubble as in boiling, or be very angry" .)