318 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



Figure 9. — The 300-mb. contour map when hurricane Carol was nearly stationary east of 

 Jacksonville, Fla. (See tropical storm symbol $.) This map portrays the pressure dis- 

 tribution at about the 30,000-foot level. The wind flow is usually almost parallel to the 

 direction of the contours (counterclockwise around the high pressure [H]) and the wind 

 speed varies inversely with the space between the contour lines. 



the transformation of a disturbance in the Tropics into a tropical storm 

 that has a vortical circulation, maximum wind speed of at least 40 

 knots, and a center in which the winds are relatively calm. The wind 

 speed, however, is more likely to be at least of hurricane intensity, that 

 is, 75 m.p.h., before the end of the inception period. Forecasts of 

 intensity are those made after the tropical storm has formed and has 

 already become a menace to the life and property of communities that 

 stand in its projected path. 



In the hurricane service, warnings are ordered for an area at any 

 time when the winds are expected to reach hurricane force. No 

 stronger warnings are issued regardless of how much the wind speed 

 is expected to exceed 75 m.p.h. The amount of damage that can be 

 done, however, varies considerably with the intensity of the storm. 



