It will show what conditions we may expect (7,5)
I believe the answer is:
weather chart
'it will show what' is the definition.
The definition suggests a singular noun which matches the answer.
'conditions we may expect' is the wordplay.
I cannot really understand how this works, but
'conditions' could be 'weather' (I've seen this before) and 'weather' is found in the answer.
The remaining letters 'chart' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for weather chart that I've seen is " Forecaster's map".)