The phrase "a low cloud of" is correct and usable in written English.
It can be used to describe a situation or atmosphere that feels heavy, oppressive, or unclear, often metaphorically.
Example: "As the meeting began, there was a low cloud of tension in the room, making everyone uneasy."
Alternatives: "a thick fog of" or "a heavy shroud of".
Outside the house, we walked around its daffodil-edged moat and looked beyond a fence to a low cloud of plum trees in full bloom, with sheep and newborn lambs munching the thick grass.
It's an evil crime, and evil stalks the pages of Irish author Tana French's fourth novel "like a low cloud of sticky black dust spreading slowly out from this room to cover the houses, the fields, blotting out the moonlight".
Less than a week into November, there was frost on the windshield when I got up for school, and the sun seemed to have vanished, replaced by a low cloud cover and winds out of the north.
The weather on 29 February 1944 was overcast with a low cloud ceiling that prevented most of the planned air strike.
By late afternoon of the 22d the sky became completely overcast with low clouds of bad weather which predominated throughout the remainder of the storm".
Low clouds of 3,000 feet (914 meters) thickness tend to mean precipitation; since you probably can't guess that height accurately from your observation point, look for the darkness.
Stars are believed to form as the result of a collapse of a low-temperature cloud of gas and dust.
Imagine a low-lying cloud of lethal chlorine gas spreading through New York City or your home town, stretching 15 miles past your childhood playground, your place of worship, or your friends' homes.
I recall standing on the shore of Cape Cod some years ago and hearing the sound of birds above the rather low cloud base of that day.
The relatively low cloud point of Triton X-114 (∼23°C) allows the separation of amphiphilic integral membrane proteins from water-soluble proteins at physiological temperatures.
A bank of low cloud also fills some mountain valleys.
