PNNL

Abstract

The Gulf Coast of Florida has seen heightened hurricane activity in recent decades with several storms making destructive landfalls over this region. On the other hand, the Atlantic Coast of Florida has not experienced similar increases over this period. In this study, we attempt to understand this regional contrast using a suite of observations for the period 1979-2024. First we demonstrate that while the El Nino Southern Oscillation (ENSO), the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO) can explain ~23% of the interannual variability in landfall frequency over the Gulf Coast, the variance explained by them for the Atlantic Coast is statistically insignificant. Next, we show that this striking difference between the two coasts may be attributed to the regional patterns of anomalous wind shear, steering flow and air-sea thermodynamic state excited by those modes of variability over the tropical Atlantic. The differential control exerted by ENSO, AMO and NAO on landfalling Florida hurricanes, in combination with decadal trends in those modes, likely play important roles in the observed increases in hurricane landfalls over Florida's Gulf Coast.