i6o 



It is apparent that where sea-surface temperatures are relatively low 

 (weaker energy exchange), hurricanes are cut off from their heat source and 

 tend to wealcen; where the sea-surface temperatures are relatively high 

 (maximum energy exchange), hurricanes tend to intensify. (Figure 6 shows the 

 spontaneous response of hurricane central pressure to the sea-surface 

 temperature field.) 



It is interesting that the facts brought out in this study would aid 

 the hurricane forecaster in predicting variations in hurricane intensity. 

 Construction of 10-day composite sea- surface temperature charts for the east 

 coast, Gulf of Mexico, or any other areas influenced by the presence of 

 tropical storms is desirable . The construction of total heat-exchange charts 

 can be performed on a mesoscale, to provide the forecaster with a better 

 understanding of potential areas of hurricane intensification or weakening 

 along its projected track. It must be realized however, that outside the 

 major shipping lanes (tropical Atlantic) lack in density of synoptic observa- 

 tions may prevent a detailed analysis . 



Numerous hurricanes, for instance the one of September 1938? of 

 September 19^^> and hurricane Hazel in 195^> have reached maximum intensity 

 in the northern latitudes. These hurricanes maintained or even increased 

 their intensity after moving over colder coastal waters or over land. These 

 effects may be attributed to polar trough intensification which affected 

 the motions of these storms and also provided new sources of energy for 

 extratropical development. (This study is intended to relate only the 

 fluctuations of the central pressure of hurricanes in relationship with the 

 sea-surface temperature pattern of storms that remained tropical in their 

 nature . ) 



Hurricane Ginny appeared to follow a track over the Gulf Stream; how- 

 ever, it is believed that this track coincided with the prevailing weak 

 steering current. There is no substantial evidence to prove that the paths 

 of hurricanes follow the warmer water bands j for instance, hurricane Esther 

 (1961) assumed a track at right angles to the alternating warm and cool 

 water masses. 



Although only a relatively small number of hurricanes has been studied 

 for determining the relationship of heat exchange v;ith hurricane pressure, 

 there is sufficient evidence that hurricane intensity is related to sea- 

 surface temperature patterns. This concept should be fully investigated. 



Acknowledgement - I am indebted to Dr. W. G. Jacobs for constructive 

 comments and criticism in preparing this study for 

 publication and to the U. S. Weather Bureau, Washington, 

 D. C, National Airport, for use of their files of 

 synoptic weather maps . 



