Table 11. Type of high clouds 

 Symbol C u — Clouds of types Cirrus, Cirrostratus , and Cirrocumulus 



Code 

 fig- 

 ures 



Technical language specifications 



No Ch clouds. 



Cirrus fibratus, sometimes un- 

 cinus, not progressively invad- 

 ing the sky. 



Cirrus spissatus, in patches or en- 

 tangled sheaves, which usually 

 do not increase and sometimes 

 seem to be the remains of the 

 upper part of a Cumulonimbus; 

 or Cirrus castellanus or floccus. 



Cirrus spissatus cumulonimbo- 

 genitus. 



Cirrus uncinus, or fibratus, or 

 both, progressively invading 

 the sky; they generally thicken 

 as a whole. 



Cirrus, often in bands, and Cirro- 

 stratus, or Cirrostratus alone, 

 progressively invading the sky; 

 they generally thicken as a 

 whole, but the continuous veil 

 does not reach 45° above the 

 horizon. 



Cirrus, often in bands, and Cirro- 

 stratus, or Cirrostratus alone, 

 progressively invading the sky; 

 they generally thicken as a 

 whole, but the continuous veil 

 extends more than 45° above 

 the horizon, without the sky 

 being totally covered. 



Cirrostratus covering the whole 

 sky. 



Cirrostratus not progressively in- 

 vading the sky, and not entirely 

 covering it. 



Cirrocumulus alone, or Cirrocu- 

 mulus predominant among the 

 cirriform clouds. 



Clouds Ch not visible owing to 

 darkness, fog, blowing dust or 

 sand or other similar phenom- 

 ena, or because of a continuous 

 layer of lower clouds. 



Plain language specifications 



No Cirrus, Cirrostratus or Cirrocu- 

 mulus. 



Cirrus in the form of filaments, 

 strands or hooks, not progressively 

 invading the sky. 



Dense Cirrus in patches or entangled 

 sheaves which usually do not in- 

 crease and sometimes seem to be 

 the remains of the upper parts of 

 Cumulonimbus; or Cirrus with 

 sproutings in the form of small tur- 

 rets or battlements or Cirrus having 

 the appearance of cumuliform tufts. 



Dense Cirrus often in the form of an 

 anvil, being the remains of the 

 upper parts of Cumulonimbus. 



Cirrus in the form of hooks or fila- 

 ments or both, progressively invad- 

 ing the sky; they generally become 

 denser as a whole. 



Cirrus, often in bands converging to- 

 wards 1 point or 2 opposite points 

 of the horizon and Cirrostratus, or 

 Cirrostratus alone; in either case 

 they are progressively invading the 

 sky, and generally growing denser 

 as a whole, but the continuous veil 

 does not reach 45° above the 

 horizon. 



Cirrus, often in bands converging to- 

 wards 1 point or 2 opposite points 

 of the horizon, and Cirrostratus, or 

 Cirrostratus alone; in either case 

 they are progressively invading the 

 sky, and generally growing denser 

 as a whole; the continuous veil ex- 

 tends more than 45° above the 

 horizon, without the sky being 

 completely covered. 



Veil of Cirrostratus covering the 

 celestial dome. 



Cirrostratus not progressively invad- 

 ing the sky, and not completely 

 covering the celestial dome. 



Cirrocumulus alone, or Cirrocumulus 

 accompanied by Cirrus or Cirro- 

 stratus or both, but Cirrocumulus is 

 predominant. 



No Cirrus, Cirrostratus or Cirrocumu- 

 lus visible owing to darkness, fog, 

 blowing dust or sand, or other 

 similar phenomena, or more often 

 because of the presence of a con- 

 tinuous layer of lower clouds. 



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