Despite the upper trough to the west and some convective potential, lightning appears unlikely across most of the British Isles during the daytime hours. A warm layer at around 700mb will inhibit deep convection and the forecast profiles are rather dry, therefore lightning potential is deemed unlikely. 

During the evening and overnight low pressure will move towards southern Ireland and instability and moisture will increase on its forward side. Rain with embedded convection is possible with an odd lightning strike, although this is also a low-end potential (greatest likely being just offshore, south of Ireland).