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Abstract Seasonal predictions of tropical cyclone (TC) landfalls are challenging because seasonal landfall count not only depends on the number and spatial distribution of TC genesis, but also whether those TCs are steered toward land or not. Past studies have separately examined genesis and landfall as a function of large-scale ocean and atmospheric environmental conditions. Here, we introduce a practical statistical framework for estimating the seasonal count of TC landfalls as the product of a Poisson model for seasonal TC genesis and a logistic model for landfall probability. We compute spatial variations in TC landfall and genesis by decomposing TC activity in the western North Pacific (WNP) basin into 10° × 10° bins, then identify coherent regions where El Niño–Southern Oscillation (ENSO) and the western extent of the Pacific subtropical high (WPSH) have significant influences on seasonal landfall count. Our framework shows that ENSO and the WPSH are weakly related to basinwide landfalls but strongly related to regional genesis and landfall probability. ENSO modulates the zonal distribution of TC genesis, consistent with past work, whereas the WPSH modulates the meridional distribution of landfall probability due to variations in steering flow associated with the Pacific subtropical high. These spatial patterns result in four coherent subregions of the WNP basin that define seasonal landfall variations: landfall count increases in the southwestern WNP during a positive WPSH and La Niña, the south-central WNP during a positive WPSH and El Niño, the eastern WNP during a negative WPSH and El Niño, and the northern WNP during a negative WPSH and La Niña.
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Interannual Variability of Tropical Cyclone Landfalls in the Eastern North Pacific: Environmental Drivers and Implications
Abstract Despite its high tropical cyclone (TC) density, the Eastern North Pacific (ENP) basin has received relatively little research attention on landfall variability. This study investigates the climatological seasonal cycle and interannual variability of TC landfalls in the ENP. We find that the basin is characterized by a bimodal distribution of landfalls, with peaks in June and September–October. Using a composite analysis of high and low landfall years, we show that this distribution is primarily driven by landfall probability rather than genesis. The absence of landfalls during July is due to enhanced easterlies from the Caribbean Low‐Level Jet entering the ENP through gaps in the Americas Cordillera. High landfall years feature enhanced easterly wind reversals from a northward‐shifted Intertropical Convergence Zone. These additional steering winds drive hurricanes ashore in the vulnerable region of southwest Mexico. This study provides valuable insights for improving TC landfall forecasts and preparedness in the region.
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- Award ID(s):
- 1945113
- PAR ID:
- 10585793
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 8
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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