Figures
 




Fig. 1. Annual incidence of named storms (tropical storms and hurricanes) versus intense-hurricane days between 1949 and 1990.

Fig. 2. Locations of 38 rainfall stations that make up the western Sahel precipitation index, as well as the 24 Gulf of Guinea precipitation stations. August-toNovember rainfall within the Gulf of Guinea region shows a predictive signal for western Sahel rainfall and hurricane activity during the following season. June-July rainfall in the western Sahel region provides a strong predictive signal for the following Augustthrough-October hurricane activity (see Landsea 1991).
 


Fig. 3. Bar graph of the early-season rainfall-anomaly index, which Includes the previous year August-November rainfall from the Gulf ofGulnea (weighted 0.30) and June.-July western Sahel rainfall (weighted 0.70). Rainfall is expressed as standardized deviations from the 42-yr average (from Landsea 1991).
 
 

Fig. 4. Comparison of intense (category 3-5) hurricane tracks stratified into six groups of seven years each based upon the early season (prior to 1 August) rainfall amounts. The top left panel includes the seven wettest individual years, and the bottom right panel is a composite of the seven driest years. (The years included in each group are listed in Table 5.)
 


Fig. 5. Plot of Julian day versus intense-hurricane activity (nine-day running mean) using data for 1886 through 1989. Note that nearly all intense-hurricane activity occurs between I August and I November.
 


Fig. 6. Illustration of the two basic U.S. coastal regions that are observed to have different hurricane destruction responses to varying amounts of seasonal West African precipitation. The approximate separation point is the Apalachee Bay at Florida (from Landsea at al. 1992).
 





Fig. 7. Portrayal of the U. S. coastal areas designated as in the vicinity of the Gulf Coast, vicinty of the Florida peninsula, and the vicinity of the East Coast (EC).
 
 

Fig. 8. Idealized rendering of the difference in composite intense-hurricane storm tracks during three years of higher West African rainfall amounts (top diagram) in contrast to a similar period of lower rainfall amounts (bottom diagram). Note the lack of track difference along the Gulf Coast, but the quite substantial difference in the western Atlantic and along the East Coast.