The phrase "a low ominous" is not correct as it is incomplete and lacks a noun to modify.
You can use it in a context where you want to describe a sound or atmosphere that is both low in volume and ominous in nature, but it needs to be part of a complete phrase.
Example: "The storm produced a low ominous rumble in the distance."
Alternatives: "a low foreboding" or "a low threatening".
A long, slow, gliding shot overlooks a car as it makes its way along a deserted mountain road, higher and higher up the pine-flecked ridges, while low, ominous music plays.
Beyond it, the Pacific was glowering slightly, and low, ominous streaks of rain splattered the sky.
But Cabrera seemed in his element in the fifth, strolling to the plate with his chest puffed, the low, ominous bass line of the Kanye West song "Mercy" thumping through the public address system.
There were no shrubberies, no disabled slots, no directional signs leading in, just this low, ominous flat-roofed building with long factory clerestories facing the lot and the seafood company.
Ooh, look, this is scary, isn't it?" The film (based on a novel by Stephen King, which it resembles in only a few plot elements) had begun, and its opening credits were under way -- a long, slow, gliding shot from a bird's-eye view overlooked a car as it made its way along an otherwise deserted mountain road, higher and higher up the pine-flecked ridges while low, ominous music played.
And it turned a Low song about ominous passion, "Monkey," into a howling maelstrom of reverb with an extended crescendo from Mr. Miller.
The third round was played under a low ceiling of clouds, with an ominous Sunday weather forecast turning the day a deeper shade of gray.
As an independent predictor of outcome at ICU admission, a low plasma glutamine concentration is an ominous sign [ 1, 2].
Of these, the factors carrying the most ominous implications are those denoting the presence of liver failure, that is, a low serum albumin, elevated bilirubin and the presence of ascites.
