Forecasting the Weather and Storms 267 



heavy ocean swell may be caused by the 

 friction of the rapidly gyrating air on 

 the surface of the water, and when the 

 hurricane has a slow progressive move- 

 ment, as it usually has south of latitude 

 30 degrees, this swell may be propagated 

 outward from the center of the storm 

 faster than the storm is moving and 

 reach the coast several hours before 

 either the barometer or the wind move- 

 ment gives any indication of the coming 

 storm. 



The tracks of West Indian hurricanes 

 are usually in the form of parabolas. 

 These storms come from the southeast, 

 but on reaching the latitude of our Gulf 

 coast they, as a rule, recurve to the 

 northeast and pass along our coast line 

 or near to it. 



Chart VIII shows a West Indian hur- 

 ricane just making its advent into 

 Florida. The effect of the storm is felt 

 as far north as Wilmington, where the 

 wind is being drawn from the northeast 

 at the rate of 24 miles per hour, and dan- 

 ger warnings, as indicated by the bars 

 on the arrows, are being displayed as 

 far north as Norfolk, both at the regu- 

 lar observation stations of the Weather 

 Bureau and at all the numerous large 

 and small harbors of the South Atlantic 

 coast. The winds at Savannah and 

 Jacksonville are moving from the north- 

 east and north, respectively, at 20 miles 

 per hour, which is four miles less than at 

 Wilmington, farther away from the 

 storm center. This apparent inconsist- 

 ency may be due to the low and re- 

 stricted exposure of the instruments at 

 the nearer stations, but not necessarily 

 so, as the winds never blow into or 

 around a storm at velocities that are 

 evenly and consistently in accord with 

 the pressure gradients, but rather in the 

 form of rising and falling gusts. 



Observe that there are no warnings 

 flying at Key West ; this is because the 

 storm center is moving away, and the 

 wind cannot therefore reach any higher 

 velocity than it now has, and must 

 steadily decline. 



In studying the winds about this 

 storm center, or rather about such part 

 of it as projects over the land, recall 

 the story about Franklin's northeast 

 storm. It will be seen how it is possible 

 for storms to progress against the wind. 

 In thunder-storms this rule does not 

 hold. They cover but an infinitesimal 

 area in comparison with a cyclone, and 

 there is a horizontal rolling of the atmos- 

 phere, caused by cold and heavy air from 

 above breaking through into a lighter 

 superheated stratum next the earth. 

 This rolling motion throws forward the 

 cool air in the direction in which the 

 cloud is moving. 



Chart IX shows a slight aberration in 

 the northeast course of the storm, which 

 places the center inland, so that the 

 whole cyclone can be charted. From 

 eastern Florida the usual course is north- 

 east over the ocean instead of up through 

 Georgia and the Carolinas. What 

 caused this storm to depart from the 

 usual course ? The reason can be easily 

 found, and it is important that one 

 should find it. The high over New 

 England and the contiguous ocean had 

 a tendency to crowd the storm inland 

 and cause it to seek the route of least re- 

 sistance, and the low over the Lake re- 

 gion attracted it. That is the reason ; 

 it will be made plainer when we come 

 to consider the translation of storms. 



The storm has been destructive to 

 marine property, the wind at Savannah 

 reaching 72 miles per hour, and 48 miles 

 at Jacksonville, and warnings are now 

 displayed at all ports northward to New 

 England, as the hurricane will move 

 northward between the two highs along 

 the lines of least pressure. Chart X 

 shows that it traveled from northern 

 Georgia to central New York during 

 the next 24 hours. The storm center 

 passing northward over the land instead 

 of the water, the hurricane winds on 

 the water were onshore — a condition 

 that strewed the coast with the wreckage 

 of many vessels that were unable to see 

 the warning signals in time to seek har- 



