Predictability of Tropical Cyclogenesis Associated with Different Development Pathways

The predictability of tropical cyclogenesis is evaluated over the North Atlantic for different genesis pathways using the Global Ensemble Forecasting System (GEFS) Reforecast Version-2. A previous study has defined five genesis pathways based on the low-level baroclinity and upper-level forcing of the genesis environmental state: non-baroclinic, low-level baroclinic, trough-induced, weak tropical-transition (TT) and strong TT pathways. It was found that genesis associated with stronger upper-level forcing (strong TT and weak TT pathways) has lower predictability than that associated with weak upper-level forcing (non-baroclinic and low-level baroclinic pathways). The different genesis predictability can be explained by the different predictability of deep tropospheric vertical shear and mid-level humidity in the vicinity of genesis.