Storm mostly circling familiar sea gets highest rating (4,5)
I believe the answer is:
gold medal
'highest rating' is the definition.
(highest award)
'storm mostly circling familiar sea' is the wordplay.
'storm mostly' becomes 'gal' (I can't justify this - if you can you should give a lot more credence to this answer).
'circling' means one lot of letters goes inside another (circling can mean going around or containing).
'familiar' becomes 'old' (I've seen this in another clue).
'sea' becomes 'med' (short for Mediterranean).
'old'+'med'='oldmed'
'gal' placed around 'oldmed' is 'GOLD MEDAL'.
'gets' acts as a link.
(Other definitions for gold medal that I've seen before include "Possible alternative to cup" , "Award for Olympic winner" , "First prize" , "prize for winning" , "top award" .)