RELATIVE TIMING OF TROPICAL STORM LIFETIME MAXIMUM INTENSITY AND TRACK RECURVATURE

An intriguing picture is emerging of coupled hack and intensity links in tropical cyclones. Since recurvature represents a dramatic track sh ift, recurving tropical storms are isolated in this study and their ti me of maximum lifetime intensity is compared to their time of recurvat ure. Thirty-one percent of all western North Pacific tropical storms a nd 28% of all such storms in North Atlantic recurve. Seventeen years o f track and intensity data for recurving tropical cyclones in these ba sins are examined here. The overwhelming majority (approximate to 80%) of western North Pacific tropical storms (including typhoons) reach t heir lifetime maximum intensity prior to recurvature. More than 45% of all recurving storms have coincident recurvature and lifetime maximum intensity, with weaker tropical storms clearly more likely to reach p eak intensity at recurvature than strong systems. Inspection of tropic al storm intensity and track data for North Atlantic systems reveals f ew clear patterns. The most robust observation to be made here is that the majority of these systems reach their peak intensity prior to rec urvature. Exclusion of landfalling extratropically transforming tropic al cyclones from this sample greatly reduces the number of systems, ma king the significance of any results questionable.