Today I noticed the dark clouds in the sky, and I decided not to take our dogs out for a walk, for fear of rain.
"dark billowing clouds" isn't a sentence. Dark and billowing are adjectives describing clouds, a plural noun.
The correct punctuation in the sentence is: "The dark clouds will lighten when the sun lowers."
The dark clouds were foreshadowing the storm that was to come.
"It is stormy outside, with dark clouds and heavy rain."
The mountains were usually lovely to look at on my drive to work, highlighted with the dawning sunlight, but winter had come and they were now cloaked and shrouded with a robe of dark clouds.
Dark storm clouds were looming on the horizon, casting a sense of impending doom over the peaceful village.
The thick, dark, gray clouds signaled that ominous weather was on its way.
The thick, dark, gray clouds signaled that ominous weather was on its way.
The dark storm clouds foreshadowed the approaching bad weather.
Dark rain Clouds are clouds that are black when it rains
Although the weather was mild, dark clouds gathered ominously on the horizon.
The dark clouds looked brooding and ominous, a violent storm was heading their way.