Related Clues:

• Telltale sign
• Sign of things to come
• Forewarning
• Sign of foreboding
• Dark clouds on the horizon, say
• Portentous event
• Dark clouds, say
• Evil sign
• Hooting owl, maybe
• *Eclipse ... black cat ... future
• Warning
• Be a sign of
• Writing on the wall
• Bodement
• Black cat, perhaps