Meteorologist from area in rainy Munster, perhaps (10)
I believe the answer is:
weatherman
'meteorologist' is the definition.
(I know that weatherman is a type of meteorologist)
'area in rainy munster perhaps' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'in' is an insertion indicator.
'rainy' becomes 'wet' (similar in meaning).
'munster perhaps' becomes 'herman' (I can't explain this - if you can you should give a lot more credence to this answer).
'a' going into 'wet' is 'weat'.
'weat'+'herman'='WEATHERMAN'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for weatherman that I've seen before include "He provides forecasts" , "Met chap" , "Fish possibly once" , "Met worker" , "Met fellow" .)