Enso signatures in landfalling Tropical Cyclones along the western Gulf of Mexico

Landfalling tropical cyclones from 1868 – 2006 along the Texas and northeast Mexico coasts were studied to determine their relationships to El Niño Southern Oscillation (ENSO). The study area was divided into six sections: the entire Texas coast, the Brownsville, Corpus Christi, and Houston, Texas County Warning Areas (CWAs), the Texas portion of the Lake Charles, Louisiana CWA, and northeast Mexico from 20º north latitude to the Texas border.

The tropical cyclone data set was obtained from the United States National Hurricane Center in Miami Florida. The only months that tropical cyclones made landfall in the study region were June through October. The landfalling tropical cyclones were divided into three groups by strength at landfall: all of the tropical cyclones, tropical cyclones of hurricane intensity, and tropical storm intensity.

The results showed that changes occurred in landfalling tropical cyclone frequency during El Niño, La Niña and neutral periods. A probability of tropical cyclone landfall in the various study areas was computed and showed that differences occurred between the various areas and the ENSO phases. The probability of landfall was greater during the La Niña phase for every area except the Houston CWA. The Houston CWA had a slightly greater probability of landfall during the neutral phase of ENSO. Each area included in this study had the least probability of landfall during the El Niño phase. Differences between the El Niño and neutral phase's landfall means and the La Niña and neutral phase's landfall means were computed. These mean differences showed that landfall was greater during the La Niña phase and least during the El Niño phase of ENSO. These research results suggest that El Niño Southern Oscillation influenced the number of tropical cyclone landfalls in this study region.