What are the potential causes of incorrect predictions of tropical cyclone intensification in medium-range ensemble forecasts?

Book excerpt: Tropical cyclones (TC) are the most destructive weather phenomena in the world. These storm systems are common in large parts of highly populated tropics and subtropics with favorable atmospheric conditions. Society’s vulnerability to them and the associated annual economic costs have risen steadily: mean worldwide insured losses averaged 75 billion USD per year in the 10 years between 2009 and 2019. Cinco et al. (2016) analyzed TC data and observed that in the period from 1951 to 2013, an average of 19.4 TCs entered the Philippine Area of Responsibility in the Western North Pacific, and nine TCs moved over the islands. Consequently, the Philippines have the highest number of landfalling storms and the highest rate of severe TC worldwide. In turn, the TCs that move over the islands into the South China Sea frequently affect the coast of Vietnam. Through a spatial assessment of TC vulnerability, Nguyen et al. (2019) have demonstrated a high or very high susceptibility in most parts of coastal Vietnam. The most extreme event over the WNP in the last century was Typhoon Haiyan, which caused 6,300 deaths and widespread economic and socioeconomic damage. This significant susceptibility implies the high importance of improving weather forecast models for greater predictive capability. In recent decades, the quality of forecasting tropical cyclone tracks has increased steadily at the European Center for Medium-Range Weather Forecast and other numerical weather prediction centers. Nevertheless, intensity predictions still present more significant challenges.