Conditions for tropical cyclone rapid intensification onset

Abstract:

Predicting the onset of tropical cyclone (TC) rapid intensification (RI) is currently a challenging yet important task in operational TC intensity forecast. Using a set of idealized simulations and real-time analyses for a range of RI, it is found that the TC structure displays a very inherent structure at the RI onset across the experiments with a warm core > 1.6K, averaged relative humidity in the storm central region > 80%, and the maximum sustained surface wind > 14 ms^-1. Sensitivity experiments with different large-scale environments reveal that the predictability of the RI onset is very sensitive to the moisture profile in the storm central region, which may account for high uncertainties in predicting the RI onset moment in real-time forecasts.