90 



ILLINOIS ACADEMY OF SCIENCE 



to the relatively stable temperature conditions. The low con- 

 stancy value in the east and northeast may be accounted for in 

 a similar manner. The presence of the Great Lakes would 

 probably increase the variability ; the average wind velocity is 

 low; and the prevailing high temperatures in the east and 

 southeast would introduce an unstable element. (The data 

 in this paragraph are based only on the A. M. observations.) 



LEGEND 

 ^Hl60-50 

 HH 50-40 

 I l 4o-an 



Figure 15. 



s 



Temperature 



The distribution of wind velocities within the cyclone is 

 given in figure 13. The average wind velocity in miles per 

 hour for each tract is indicated by the number inscribed in the 

 small circle. The variation in wind velocity may be separated 

 into two components. First : the shaded areas show that the 

 higher wind velocities prevail in the west and northwest while 

 the lower velocities occur to the southeast of the center. This 

 condition is a direct consequence of the pressure distribution 



