Table 8. Type of low clouds 



Symbol C L — Clouds of types Stratocumulus, Stratus, Cumulus, 



and Cumulonimbus 



Code 



fig- 



ures 



Technical language specifications 



Plain language specifications 



No Cl clouds. 



Cumulus humilis, or Cumulus 

 fractus other than of bad 

 weather, or both. 



Cumulus mediocris or congestus, 

 with or without Cumulus of 

 species fractus or humilis, or 

 Stratocumulus; all having their 

 bases at the same level. 



Cumulonimbus calvus, with or 

 without Cumulus, Stratocumu- 

 lus or Stratus. 



Stratocumulus cumulogenitus 



Stratocumulus other than Strato- 

 cumulus cumulogenitus. 



Stratus nebulosus or Stratus frac- 

 tus other than of bad weather, 

 or both. 



Stratus fractus or Cumulus frac- 

 tus of bad weather or both 

 (pannus) usually below Alto- 

 stratus or Nimbostratus. 



Cumulus and Stratocumulus, 

 other than Stratocumulus cu- 

 mulogenitus, with bases at dif- 

 ferent levels. 



Cumulonimbus capillatus (often 

 with an anvil), with or without 

 Cumulonimbus calvus, Cumu- 

 lus, Stratocumulus, Stratus or 

 pannus. 



Clouds C L not visible owing to 

 darkness, fog, blowing dust or 

 sand, or other similar phe- 

 nomena. 



No Cumulus, Cumulonimbus, Strato- 

 cumulus or Stratus. 



Cumulus with little vertical extent 

 and seemingly flattened, or ragged 

 Cumulus other than of bad weather, 

 or both. 



Cumulus of moderate or strong verti- 

 cal extent generally with protuber- 

 ances in the form of domes or 

 towers, either accompanied or not 

 by other Cumulus or by Strato- 

 cumulus; all having their bases at 

 the same level. 



Cumulonimbus the summits of which, 

 at least partially, lack sharp out- 

 lines, but are neither clearly fibrous 

 (cirriform), nor in the form of an 

 anvil; Cumulus, Stratocumulus or 

 Stratus may be present. 



Stratocumulus formed by the spread- 

 ing out of Cumulus; Cumulus may 

 also be present. 



Stratocumulus not resulting from the 

 spreading out of Cumulus. 



Stratus in a more or less continuous 

 sheet or layer, or in ragged shreds 

 or both, but no Stratus fractus of 

 bad weather. 



Stratus fractus of bad weather or 

 Cumulus fractus of bad weather 

 or both (pannus) usually below 

 Altostratus or Nimbostratus. 



Cumulus and Stratocumulus, other 

 than those formed from the spread- 

 ing out of Cumulus; the base of 

 Cumulus is at a different level than 

 that of the Stratocumulus. 



Cumulonimbus, the upper part of 

 which is clearly fibrous (cirriform) 

 often in the form of an anvil; either 

 accompanied, or not by Cumulo- 

 nimbus without anvil or fibrous 

 upper part, by Cumulus, Strato- 

 cumulus, Stratus, or pannus. 



No Cumulus, Cumulonimbus, Strato- 

 cumulus or Stratus visible owing to 

 darkness, fog, blowing dust or 

 sand, or other similar phenomena. 



Note: "Bad Weather" denotes the conditions 

 precipitation and a short time before and after. 



which generally exist during 



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