Thundery weather (5)
I believe the answer is:
storm
'thundery weather' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for storm that I've seen before include "Sudden attack" , "Violent weather; shout angrily" , "Shout angrily, assault" , "Feature of weather" , "Atmospheric disturbance, assault (stronghold)," .)