In the post-frontal environment, the passage of a pronounced shortwave trough during the afternoon and early evening will provide the focus for an increase in coverage of showers and a few thunderstorms as cool air aloft markedly steepens mid-level lapse rates - beginning in W Connaught / W Ulster mid afternoon, then spreading ENE towards SW Scotland during the evening. Strong DLS and notable LLS could allow convection to become well-organised, at least for a time, with potential for strong, gusty winds and perhaps a tornado. Hail with diameter up to 1.5cm will also be possible.

Showers will continue overnight, though with lapse rates looking less impressive and so lightning will be more isolated / sporadic - the risk then extending towards W/SW Ireland later in the night.