Lowering

To appear gloomy; overcast.

He answered and said unto them, When it is evening, ye say, It will be fair weather: for the sky is red. And in the morning, It will be foul weather to day: for the sky is red and LOWERING. O ye hypocrites, ye can discern the face of the sky; but can ye not discern the signs of the times? ( Matthew 16:3 )