Towards afternoon, cirrocumulus and cirrostratus began to appear moving northward.
Cirri and cirrostratus clouds have been very prevalent during the day, and cumulostratus during the night.
Night clear and very cold; no wind; towards morning, sky became slightly overcast with cirrostratus clouds.
Plural cirrostrati (sîr'ō-strāt'ī')
A thin, hazy, high-altitude cloud composed of ice crystals, often covering the sky in sheets and producing a halo effect around the sun. Cirrostratus clouds generally form between 6,100 and 12,200 m (20,000 and 40,000 ft). See illustration at cloud.