Meaning of storm warning

storm' warn"ing

Pronunciation: [key]
  1. a showing of storm signals.
  2. a National Weather Service warning of winds having speeds of 48 knots (55 mph, 25 m/sec) or greater. Cf.(def. 3).
  3. any sign of approaching trouble: The troops on the border were a storm warning, and we prepared for war. His angry look was a storm warning.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.