storm cloud

storm cloud (plural storm clouds)

1. (meteorology) A dark and ominous cloud that appears to indicate a coming storm.
   • 2023 March 8, Christian Wolmar, “Labour passes up the chance to deliver a forceful rail policy”, in RAIL, number 978, page 35:

     Uncertainty hangs over the industry like a storm cloud on a summer's day, preventing long-term planning and investment.

• thundercloud