258 



THE WEATHER 



pressure at the center had remained 29.60 and the storm had 

 moved twice as fast, would that have affected the rate of the 

 change in pressure? Explain. 



NOTE. The so-called "indications" sometimes printed on the dials 

 of aneroid barometers are not reliable. 



282. How the Winds Shifted. Figure 182 shows the wind 

 directions in solid arrows at a few places on the 5th when the 

 center of the LOW was at Omaha, and in broken arrows on the 

 6th when the center was near Detroit. The winds of each day 



FIG. 182. Changes of the wind, with the passing of a low, December 5-6, 



1906. 



circle about the center of the LOW. The combined figure shows 

 how the wind changed at different places as the LOW passed 

 eastward. Notice how the wind shifted at places north of the 

 track of the storm center; and how it shifted at places south of 

 the track. Note also the shift at Des Moines which was 

 directly in the path of the center. 



283. General Rule. The winds of a circular LOW always 

 shift in the manner shown in Fig. 182. If the wind in a storm 

 changes gradually from east through north to northwest, it is 

 said to be a " backing wind" and the center of the LOW is pass- 



