In a remarkably similar fashion to Monday, elevated convection (showers and perhaps a weak thunderstorm) may be ongoing over the NW Midlands / N Wales on Tuesday morning courtesy of a minor shortwave, but this will relax to the west with time. Otherwise, diurnal heating will eventually yield 500-1,000 J/kg CAPE, with convergence zones and orographic forcing providing the primary triggers for deep convection to develop, at least initially. Storm motion will be very slow, generally 10-15mph to the NW across Britain and W or SW over Ireland - this brings the risk of localised flash flooding given high moisture content and prolonged downpours. Bulk shear will be weaker than on Monday, generally greatest around midday at 20-25kts, reducing to 15-20kts by evening. Hence showers and storms will tend to pulse, although may become a little organised for a time during the midday/early afternoon period. The most intense cells may produce hail up to 1.5cm in diameter.

Towards late afternoon another shortwave will drift northwards across Wales / Midlands / East Anglia / London and this may encourage more widespread shower and thunderstorm activity that may persist well into the evening hours, especially focussed near pre-existing boundaries. Low-level vorticity near such boundaries may be ingested into updrafts to bring the potential for a few funnel clouds or a weak tornado. 

Showers and thunderstorms could persist until late evening in some areas, but will generally become weaker as nocturnal cooling of the boundary layer occurs later in the day. However, some elevated shower and thunderstorm activity may persist, or actually increase, across SW Scotland, the Irish Sea and into E / NE Ireland through Tuesday night into early Wednesday as the aforementioned shortwave over England/Wales swings westwards through the night. Some showery rain may also push from France towards S / SE England overnight, which could produce a few isolated lightning strikes.