This is a charade - where two or more words are joined together to form the answer. Look for parts of the clue that can be split into separate definitions.
Split this into two parts: 'forecaster' gives you one word, and 'spot' (as in to see something) gives you another word. Put them together in order.
Answer: SIGHTSEER | A charade of SIGHT ('spot' - to see) and SEER ('forecaster') = SIGHTSEER (tourist)