ireful

1. (of clouds, the sky, etc) Threatening to storm, or storming; louring or stormy.Examples: "... ireful clouds collect in stern array, / And bursting thunders speak the mighty fray;"; "... ireful crimson sky, as he gropes his broken way home after the trial."; "... ireful clouds, as foreboding a day for starting a mission as Bennie and Sadie Mays could recall—and the weather became a nagging portent that lingered in their minds during a warm reception filled with hope and promises."