SKY AND CLOUDS IN A TYPICAL DISTURBANCE 



The accompanying diagram, taken from the International Atlas, 

 shows the distribution of cloud and sky types in the various sectors of 

 a typical disturbance. 



In identifying cloud and sky types, observers in the United States 

 should be guided by the photographs and not by the position of the 

 clouds in the disturbance. The following notes are taken from the 

 International Atlas: 



1. This diagram corresponds with a typical disturbance — to be 

 precise, the first of a family — arriving from the west in western Europe. 



H, 

 L, 



H2 



rroni\ 



\ 

 I 



I— 



"6114/ 



Zone I 



'9.^^:^yk L, H, 



-Connecf /ng =nr _ . _- 

 ^rZone ^ — '- — ^ 



2. It sometimes happens that the rear zone is much more extensive 

 and that it persists for several days over the same region. 



3. Fractocumulus may occur practically anywhere in the rear zone. 



4. The specifications Mg and M9 correspond respectively with the 

 front or lateral sector and with the central or rear sector of a thunder- 

 storm disturbance. They can find no place in this diagram which is 

 that of a normal disturbance. 



5. Observers should not take the form of cloud corresponding with 

 the position in this diagram as necessarily determining the form of 

 cloud to be reported. 



35 



