These showers will become increasingly confined to Devon/Cornwall as the morning progresses, and while most NWP guidance remains rather unenthusiastic there is scope for an uptick in lightning potential as a minor shortwave passes close to Cornwall late morning into the afternoon, perhaps allowing deeper convection to develop. Confidence is not particularly high, so the SLGT should be treated as a low-end (i.e. near 30%). Shear is weak, so any thunderstorms that do occur will be rather pulse-type in nature and probably largely elevated. Main threat, therefore, will be local rain accumulations causing some surface water issues. Any showers/storms that do occur will gradually fade during the evening hours, though further elevated showers are possible on Monday night over the English Channel, perhaps getting close to the south coast at times.