Meanwhile, an active cold front will migrate eastwards across Ireland during Sunday daytime, with a substantial wind shift and thermal gradient. As such, line convection is expected with a brief period of heavy rain and gusty winds. It seems likely this will intensify along the cold front during the evening hours as it crosses the Irish/Celtic Seas, into Wales/SW England from midnight onwards as the Atlantic upper trough becomes increasingly negatively-tilted and PVA increases in the vicinity of the front. Pressure falls will increase across Wales/SW England, and later into the West Midlands, perhaps as much as 5mb per 3 hours with one or more small surface lows forming along the frontal boundary.

These indicators, based on climatology, would suggest a risk of tornadoes (however brief) as a Line Echo Wave Pattern develops, aided/distorted by local orography. Lightning potential is always difficult to judge along squally cold fronts as often the convection is rather shallow in depth with saturated profiles, in an otherwise low CAPE high shear environment. However, there is reason to think a few sporadic strikes may occur, perhaps more especially over SW England and the West Country (Devon / Somerset / Wiltshire / Dorset). Torrential rain and very gusty winds are still likely, whether lightning occurs or not - some guidance flags the potential for 60-70mph gusts offshore and near some coasts of SW England, for example. A SVR is therefore issued for localised damaging wind gusts, and the potential for isolated tornadoes - however it should be stressed that most areas within the SVR may not necessarily experience severe conditions.

The final area of interest is the post-frontal environment, as notably cold air aloft associated with approaching upper trough overspreads warm SSTs. Numerous showers will develop over the Atlantic and Celtic Sea, feeding into western Ireland and late in the night into western Scotland, Wales and SW England. Given a few hundred J/kg CAPE and steep mid-level lapse rates, a few sporadic lightning strikes will be possible - especially where showers move inland and are forced over high ground. However, the risk in any one location is too low to justify a SLGT at present.