'Ominous' in the Bible

And a great sign [warning of an ominous and frightening future event] appeared in heaven: a woman clothed with the sun, with the moon beneath her feet, and on her head a crown of twelve stars.

Then another sign [of warning] was seen in heaven: behold, a great fiery red dragon (Satan) with seven heads and ten horns, and on his heads were seven royal crowns (diadems).

Then I saw another sign in heaven, great and wonderful [a warning of terrifying and horrible events]: seven angels who had seven plagues (afflictions, calamities), which are the last, because with them the wrath of God is finished [that is, it is completely expressed and reaches its zenith].