Small chance of an isolated elevated thunderstorm early in the forecast period. Residual moisture in the low/mid-levels might provide the focus for a few heavy showers and / or isolated surface-based thunderstorms during the late morning/midday hours in particular with some insolation and low-level wind convergence aiding shower development as a cold front approaches from the west. Mid-level lapse rates are marginal but a low-end SLGT has been issued, with the proviso that the risk will rapidly diminish during the afternoon hours as the cold front clears and lower dewpoint air advects eastwards, despite being theoretically during the period of peak daytime heating.

Embedded lightning could occur along and/or to the east of the frontal boundary affecting northeast Scotland, which will slowly lift to the northeast during the day. Some uncertainty as to how much lightning activity there will be, but the risk deemed significant enough to issue a low-end SLGT at least. Some localised flash flooding may occur from prolonged downpours.

Cut-off upper vortex will be centred west of Ireland on Thursday, but with a trough axis pivoting northwards across the Republic of Ireland into Northern Ireland. The associated steep mid-level lapse rates will be best phased with diurnal heating over northern areas by the afternoon hours, with numerous showers, some perhaps weakly-electrified. Chance of an isolated funnel cloud.

Through the evening hours, a couple semi-organised occlusions will move east across Eire to the Celtic Sea, with some elements of line convection (and perhaps isolated lightning) given a strongly sheared environment - this will be getting close to Cornwall by 6z Friday.