In Snowdonia at present (3)
I believe the answer is:
now
'at present' is the definition.
(synonyms)
'in snowdonia' is the wordplay.
'in' indicates a hidden word.
'NOW' is hidden in the letters of 'snowdonia'.
(Other definitions for now that I've seen before include "Today" , "straight away" , "At this moment in time" , "At present, this instant" , "Immediately" .)