TABLE 24 (Cont'd) 

 Conversion from 1936 International Meteorological Organization Code to the 



WMO Code if- 501 



30 

 31 

 32 

 33 

 3k 

 35 

 36 

 37 

 38 

 39 



40 

 41 

 42 



h3 

 44 



J^5 

 46 



47 

 48 



i^9 



DUST STORMS AND STORMS OF DRIFTING SNOW 

 (Vlsitiility less than 1,000 m., 1,100 yards) 



Dust or sand storm. 

 Dust or sand storm, has decreased. 

 Dust or sand storm, no appreciable change 

 Dust or sand storm, has increased. 

 Line of dust storms. 

 Storm of drifting snow. 

 Slight storm of drifting snow- 

 Heavy storm of drifting snow 

 Slight storm of drifting snow 

 Heavy^ storm of drifting snow 



generally low. 

 generally high. 



"WMO 

 Code 

 4501 

 (modified) 



3 

 3 

 3 

 3 



3 

 3 

 3 

 3 

 3 



FOG 



(visibility less than 1,000 m., 1,100 yards) 



Fog. 



Moderate fog in last hour | ^^^ ^^^ ^^ ^^e o^. observation. 



Thick fog in last hour J 



Fog, sky discernible 



Fog, sky not discernible 



Fog, sky discernible 



I has become thinner during last hour. 



Fog, sky discernible 

 Fog, sky not discernible 

 Fog in patches. 



has begun or become thicker during 

 last hour 



DRIZZLE 

 (Precipitation consisting of numerous minute drops) 



slight drizzle, 

 moderate drizzle . 

 thick drizzle. 



J drizzle and rain. 



4 

 4 

 4 



4 

 4 



Fog, sky discernible 1 ^ appreciable change during last hour , 

 Fog, sky not discernible ) 4 



4 

 4 

 4 



5 

 5 

 5 

 5 

 5 

 5 

 5 



5 

 5 



61 



