Diurnal Variations in the Landfall Times of Tropical Cyclones over the Eastern United States

Best track tropical cyclone data are examined for the period 1950–96 to estimate the landfall times of all tropical storms and hurricanes over the coastal margins of the eastern United States. The analysis reveals a marked diurnal pattern with tropical cyclones making landfall more frequently during the evening and midmorning hours. Lulls in cyclone landfall are identified during the afternoon and early in the morning. Weak hurricanes display the strongest diurnal cycle of landfall. Category 3 and stronger hurricanes display little diurnal variation in landfall time. An examination of the diurnal pattern of cyclone passages within 300 km of the coast reveals that the pattern is most coherent and displays the greatest statistical significance at the coastline (i.e., points of cyclone landfall).