The presence of the Death Eaters outside increased the ominous mood inside number twelve.
Harry saw the Death Eaters swerve out of sight to avoid the deadly trail of flame, and at the same time felt the sidecar sway ominously: Its metal connections to the bike had splintered with the force of acceleration.
All of them looked upward in time to see the crystal chandelier tremble; then, with a creak and an ominous jingling, it began to fall.
repeated Aberforth ominously.
Harry had an ominous feeling now; he wondered whether Bill guessed more than he was letting on.
The twig flew up from the ground, spun through the air as if caught by a gust of wind, then zoomed directly at the trunk through the Willow’s ominously swaying branches.
There are no more uses of "ominous" in the book.
Show samples from other sources
I’m beginning to hear ominous rumblings of discontent.
With the clouds looking so ominous, I’m afraid there will be a bad storm.