"a baleful look" "forbidding thunderclouds" "his tone became menacing" "ominous rumblings of discontent" "sinister storm clouds" "a sinister smile" "his threatening behavior"

"ill omens" "ill predictions" "my words with inauspicious thunderings shook heaven"- P.B.Shelley "a dead and ominous silence prevailed" "a by-election at a time highly unpropitious for the Government"