ENGLAND and WALES

At 6z on Sunday an ongoing area of rain with embedded convection is likely to be stretched from southern Scotland/NW England through the Irish and Celtic Seas moving eastwards.  The best instability will be displaced from the before mentioned cold front, existing across E Anglia and SE England (up to 1,000 J/kg), and this area will likely remain capped by a layer of warmer air at around 800mb. Convective development in the deeper instability remains unlikely at this stage, although cannot be completely ruled out (one or two models have suggested an isolated heavy shower or thunderstorm may develop). 

As the cold front tracks eastwards forcing will become weaker and rain will become patchier, although some embedded convection remains a possibility along and just ahead of the front as it clears eastern England between mid-afternoon and late evening. An area through N-Cen / NE England is favoured for any more widespread lightning potential, and has the greatest potential for upgrade to slight. 

Northwestern IRELAND and western SCOTLAND

Behind the cold front and around and near the low centre, weak instability, but a moist and highly sheared environment may help to produce some heavier convection with the low end risk of lightning. Although mean winds will be strong, there would also be the small risk of an isolated tornado or two in this area in any stronger convection. 

With all of that stated, only a low risk of lightning seems appropriate at this stage, but we will continue to monitor trends for an upgrade if required.