The clouds that had rain in them were usually called nimbostratus.

When rain falls from stratus clouds they are mostly called nimbostratus.

It is common for a stratus to form on a weak warm front, rather than the usual nimbostratus.

The cloud layer achieves significant vertical extent as it lowers and changes into nimbostratus.

Lightning from an embedded cumulonimbus cloud may interact with the nimbostratus but only in the immediate area around it.

Nimbostratus and some cumulus clouds in this family usually only achieve comparatively moderate vertical extent.

Often, when an altostratus cloud thickens and descends into lower altitudes, it will become nimbostratus.

If the precipitation increases in persistence and intensity, the altostratus cloud may thicken into nimbostratus.

Nimbostratus (Ns)

The Mariestopes slid through a layer of nimbostratus and settled on its haunches in a distant part of the field.

As the low and the warm front pass, the nimbostratus thins out into low stratus and the precipitation tapers off.

Then came the rain from the cumulonimbus, failing ten miles, right through the nimbostratus, and crashing in great sheets upon the rough waters of the Usselmeer.

Nimbostratus, Stratus cloud, Altostratus cloud and stratocumulus clouds all have a smooth gray appearance.

Fractonimbus exist only under precipitation clouds (such as nimbostratus, altostratus or cumulonimbus), and don't produce precipitation themselves.

Scud clouds, a type of fractus cloud, are low, detached, irregular clouds found beneath nimbostratus or cumulonimbus clouds.

Nimbostratus usually has a thickness of about 2000 m. Though found worldwide, nimbostratus is found more commonly in the middle latitudes.

Usually, nimbostratus is a sign of steady moderate to heavy precipitation, as opposed to the shorter period of typically heavier precipitation released by a cumulonimbus cloud.

Of the latter, upward-growing cumulus mediocris produces only isolated light showers, while downward growing nimbostratus is capable of heavier, more extensive precipitation.

Conversely, nimbostratus is coded as middle because it usually initially forms at mid-altitudes of the troposphere and becomes vertically developed by growing downward into the low altitude range.

The occurrence of cumulonimbus and nimbostratus together is uncommon, and usually only nimbostratus is found at a warm front.

Downward-growing nimbostratus is then classified either as low to denote its normal base height range, or as middle, based on the altitude range at which it normally forms.

They comprise two or three genera depending on the system of height classification being used: altostratus, altocumulus, and, according to WMO classification, nimbostratus.

Nimbostreatus fractus is a variation of nimbostratus and will sometimes occur as a weather front clears, these being areas of dark rain bearing clouds with lighter altostratus between.

If the cirrostratus is broken fibratus it can mean that the front is weak and that stratus rather than nimbostratus will be the rain cloud (meaning drizzle instead of moderate rain).

Virga is a feature seen with clouds producing precipitation that evaporates before reaching the ground, these being of the genera cirrocumulus, altocumulus, altostratus, nimbostratus, stratocumulus, cumulus, and cumulonimbus.