Nonetheless, diurnal heating and low-level convergence / orographic forcing will once again be responsible for producing isolated showers and thunderstorms, particularly over high ground, but much more isolated / less-widespread than was the case on Tuesday. DLS increases through the day as the upper jet strengthens and digs southwards along the eastern flank of the upper ridge. The strongest cells may produce hail up to 1.0cm in diameter, with an ongoing risk of localised flash flooding from prolonged downpours, especially on any saturated ground following previous days showers.