262 



THE WEATHER 



of north. The rapidity of the storm's approach and its intensity will 

 be indicated by the rate and the amount of the fall in the barometer." 



286. How the Temperature Changed. Figure 187 shows 

 the temperature changes in a circular LOW as the storm 

 traveled eastward. The isotherms of the 5th are solid lines; 

 those of the 6th are broken lines. Notice that in front of 

 the LOW the isotherms moved northward as the LOW ap- 

 proached; and in the rear they moved southward as the LOW 



FIG. 187. Temperature change with the passing of a low. 



departed. What temperature change does that indicate in 

 front of a LOW? Behind a LOW? How much was the change 

 in 24 hours at Pittsburg? At Omaha? 



In an oblong or elliptical LOW the temperature changes are 

 often grouped nearer the axis of the LOW, and the temperature 

 fall is more rapid just after the axis passes. If the LOWS of 

 Figs. 180 and 186 both travel 40 miles per hour, how much 

 would the temperature at Davenport change in each case, in 

 eight hours? Also, at St. Paul? At Memphis? 



