na-adjective, noun which may take the genitive case particle 'no'
stormy; threatening (weather)
Describes weather that looks like it will become stormy, or figuratively a situation that seems about to turn turbulent.
空が荒れ模様だから、傘を持って行ったほうがいい。
The sky looks stormy, so you'd better take an umbrella.
会議は荒れ模様で、意見が激しく対立
The meeting was stormy, with opinions clashing fiercely.