nimbostratus is a dark gray cloud that forms when a front of warm, moist air meets a mass of relatively cool air. When you’re under a nimbostratus layer, you often can’t even see the cloud itself because of the rain and the thick mist formed by evaporation. If the air becomes saturated enough, another layer of ragged, swift clouds called scud can form below the nimbostratus. When you see this type of cloud coming, you might as well settle in with a good book or find an old movie marathon on TV, because it’s probably going to rain or snow for quite a while.
