Ensemble prediction of Mediterranean high-impact events using potential vorticity perturbations. Part II: Adjoint-derived sensitivity zones

► Two EPSs perturbing initial and boundary conditions through the PV field are built. ► One EPS perturbs following the 3D PV features showing intense values or gradients. ► The other EPS perturbs guided by the MM5 adjoint derived sensitivity zones. ► Both EPSs are tested on western Mediterranean high-impact weather events. ► The PV-gradient EPS shows better skill/computational-cost ratio than the PV-adjoint.