Ahead of this occlusion, some marginal instability may develop as a result of diurnal heating and thermal trough aloft, with scattered showers possible from late morning onwards over East Anglia / north Midlands / northern England before the showery rain arrives from the southwest later in the day. Some isolated lightning activity may be possible from these heavy showers.

Behind the occlusion, an uptick of instability is expected and here the better chance of some sporadic lightning is more likely. However, any such convection will be rather disorganised given a lack of any notable shear, and mainly forced by areas of low-level convergence - such as the north Devon / Somerset coast into south Wales, and close to the surface low centre over S/SW Ireland. Hesitant to issue SLGTs given the uncertainty, not least with how quickly the occlusion will lift north to allow sunshine to return to the W Country, for example - but have issued 2 low-end SLGTs for now to highlight areas with the best overall potential for some sporadic lightning activity.

The strongest cells will be capable of producing some hail up to 1.0cm in diameter, and perhaps a weak tornado.