Israeli port’s condition, enveloped in a lot of sea mist (5)
I believe the answer is:
haifa
'israeli port's' is the definition.
(I've seen this before)
'condition enveloped in a lot of sea mist' is the wordplay.
'condition' becomes 'if' (as in 'a big if').
'enveloped in' is an insertion indicator.
'a lot of' means to remove the last letter (a lot of but not all of the word).
'sea mist' becomes 'haar' (I've seen this before).
'haar' with its final letter removed is 'haa'.
'if' inserted into 'haa' is 'HAIFA'.
(Other definitions for haifa that I've seen before include "Israel's main port" , "Middle East city" , "Seaside city" , "Mediterranean port" , "Seaport in Israel" .)