Impending

"The clouds were low and hairy in the skies,
Like locks blown forward in the gleam of eyes..." 

          --Robert Frost, "Once by the Pacific" 

"The change of elevation had done nothing to alter her mood.  It was four o'clock of a sultry, overcast, oppressive afternoon, and sullen stillness had fallen on the world.  The heatwave which for the past two weeks had been grilling England was in the uncomfortable process of working up to a thunderstorm.  Shropshire, under a leaden sky, had taken on a sinister and a brooding air."  

      -- P.G. Wodehouse, Heavy Weather

"Dusk was closing down on the forbidding day.  Sue, looking out over her battlements, became conscious of an added touch of the sinister in the view beneath her.  It was the hour when ghouls are abroad, and there seemed no reason why such ghouls should not decide to pay a visit on this roof on which she stood.  She came to the conclusion that she had been here long enough." 

       -- P.G. Wodehouse, Heavy Weather