HURRICANES — GENTRY AND SIMPSON 



317 



SURFACE 



0030Z 



20 SEPT. 1955 



Figure 8. — Surface weather map at the time when hurricane lone was moving very slowly 



toward the east-northeast. 



The effect of the upper air flow on the movement of hurricane lone 

 is shown in figure 11. At the time the map was made, hurricane lone 

 was beginning to move toward the east-northeast. The contour lines 

 indicate a strong flow from the west only a short distance north of 

 hurricane lone and this indicates that hurricane lone could not move 

 very rapidly toward the north. (The wind direction and speed in 

 knots are indicated on the map for Washington, D. C, Portland, 

 Maine, and Nantucket, R. I. Several hours earlier when the storm 

 center was still over North Carolina the high-level circulation was not 

 as well defined and it was not obvious in which direction lone would 

 move. ) A few hours after the time of the map, hurricane lone drifted 

 far enough north to be affected by the strong winds blowing toward 

 the east-northeast and accelerated rapidly in forward movement. 



3. INTENSITY 



The third major forecasting problem for hurricanes is that of fore- 

 casting intensity, which to some extent, overlaps the problem of fore- 

 casting inception. As used here, forecasting of inception refers to 



