This study documents the frequency variation of landfalling-hurricanes and tropical storms in North Carolina (NC) from 1987-1999 using Empirical Mode Decomposition (EMD) method. Four principal modes, which include an interannual mode, an intra-decadal mode, a decadal mode and a multi-decadal mode, have been extracted from the NC TC landfall time series. There is evidence that the interannual mode is influenced by the El Nino/Southern Oscillation (ENSO) cycle, whereas the decadal mode is affected by the dipole mode of the Atlantic sea-surface temperature (SST) anomalies. The physical mechanisms of the intra-decadal and multi-decadal modes are not yet well understood. However, the latter seems correlated with the multi-decadal signal of West Africa rainfall anomalies. We also note that, on century time scale, the annual number of landfalling TCs in NC experienced a slight downward trend from 0.85 in the late nineteenth century to a low of 0.79 in 1950s, and has been slowly rising to about 0.81 in 1999. On decadal time scales, late 1880s-1890s, 1920s-early 1930s, late 1940s-1950s, and late 1980s-1990s experienced more than normal landfall TCs in NC, whereas 1910s-early 1920s, 1930s-early 1940s, and late 1960s-early 1980s experienced below normal TC activity in NC. All modes except the interannual mode seem to remain as positive anomalies in the early 21st century. Thus, unless interannual-time scale forcing which is unfavorable for TCs making landfall in NC exists, North Carolinians will likely brace for more than normal landfalling TCs in the early 21st century.
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