Diurnal heating across northern England, much of Scotland and perhaps NW Ireland will yield several hundred J/kg CAPE, and scope for numerous heavy showers to develop aided by orographic forcing and low-level convergence. As with previous days, the moist airmass (dewpoints 13-16C), reasonably steep low-level lapse rates and vorticity stretching could yield a few funnel clouds/weak tornadoes. Lightning activity is uncertain - there is evidence of weak upper ridging across northern England, with a dry mid-troposphere and generally stable conditions above 600mb, and this will generally restrict the depth of convection to around 5-6km (close to 20,000ft). A few stronger updrafts may be able to push closer to 7km/23,000ft where some slightly stronger mid-level flow is then available. As such, a few isolated lightning strikes could occur just about anywhere where a sufficiently strong cell can develop, but trying to pinpoint exactly where this may occur is difficult. The greatest risk appears to be northern Scotland where profiles look more unstable/moister with depth, and aided by a subtle shortwave running northwards in the afternoon. The main hazards will be the risk of local flash flooding given slow cell movement and the potential for multiple cells to train over similar areas given steering flow near-parallel to hill/mountain ranges responsible for initiation - for example the Pennines into SE Scotland. A couple of funnel clouds/weak tornadoes may also be possible associated with showers developing in Cen / S / SW Ireland in the slacker flow that evolves here during the day.

Elsewhere, showery outbreaks of rain spreading eastwards from Ireland into England, Wales and the English Channel could potentially produce a few isolated lightning strikes in places given some weak embedded instability - but again attempting to identify specific regions at greatest risk is going to be difficult. Overall, profiles become gradually more unstable through the overnight period across the central/eastern English Channel and adjacent land areas (including the Channel Islands) - but confidence is too low at this stage to consider higher threat levels. Even if very little lightning activity occurs, some guidance suggests some potentially concerning amounts of rain in parts of southern England. A SLGT may be issued later today if confidence on lightning activity increases.