Sharpening upper trough aligned Poland - Tunisia will encourage yet another day of severe thunderstorms across eastern Europe and the northern Balkans on Monday, with all severe hazards possible (large hail, severe wind gusts and tornadoes). Meanwhile, over the British Isles comparatively benign conditions are expected beneath a fairly strong jet streak aloft and a fairly complex frontal system crossing England and Wales - likely to lead to a split cold front regime with a well-marked shallow moist zone (SMZ) behind the main area of frontal precipitation.

Surface dewpoints remain at 14-15C into the afternoon (after morning rain), and although extensive low cloud seems likely in the SMZ, any breaks that develop to allow some diurnal heating, coupled with strong DLS and some areas of low-level convergence, perhaps along the trailing cold frontal boundary, may allow some elements of convection to occur in linear fashion parallel to the flow. Hence a few lines of showers may develop, although the depth of convection will be limited by very dry profiles above 600mb - and so lightning potential remains quite low, hence the broad LOW threat level issued. In fact, it is plausible that there may be no lightning at all, just a few heavy showers. Such events typically produce rather turbulent-looking low cloud bases.