...Portugal and Spain...
As the cut-off low starts to move NEward, QG lift is expected to develop over the western half of the Iberian Peninsula. About 1000 J/kg MLCAPE should become available per numerical guidance, as somewhat moister low-level air is advected northward across the western half of the peninsula.
Here, wind shear is expected to become strong with about 30 m/s expected by Sunday evening, suggesting that storms will easily acquire rotating updraughts. Such storms will are expected to produce large hail and locally severe winds. A small threat of tornadoes will exist as well.
It is possible, however, that a large fraction of storms will not be individual supercells, but be part of large clusters. Since these will probably be oriented along the flow, very high rainfall accumulations may locally occur, especially where such systems interact with orography.