ominously
adverb /ˈɒmɪnəsli/
  /ˈɑːmɪnəsli/
- in a way that suggests that something bad is going to happen in the future
- Thunder rumbled ominously overhead.
 - The streets were ominously quiet.
 
Oxford Collocations DictionaryOminously is used with these adjectives:- silent
 
- echo