Abstract/Summary

The UK Met Office decadal prediction system DePreSys4 shows skill in predicting the number of tropical cyclones (TCs) over the eastern Pacific and tropical Atlantic Ocean up to a decade ahead. The high skill in predicting the number of TCs is due to the ability to predict multi-annual-to-multi-decadal trends and variability in the number of TCs associated with the temporal evolution of surface temperature and vertical wind shear in these two ocean basins. This is further related to the simulation of the externally forced response, with internal climate variability also allowing the improvement of the prediction skill. We applied a signal-to-noise calibration framework to further increase the skill of the TC decadal prediction. The decadal skill in predicting the number of TCs over the eastern Pacific and tropical Atlantic Ocean can be up to ACC=0.93 and ACC=0.83, retrospectively (measured by the Anomaly Coefficient Correlation—ACC). DePreSys4 predicts that the number of TCs will increase in the next decade (2023–2030) over the eastern Pacific and the tropical Atlantic Ocean, potentially leading to high economic losses.