The Met Office issued a yellow UK storm warning at 5.24pm on Monday, June 22, covering parts of the South West until 9pm. The alert put people in Bath and North East Somerset, Bristol, Gloucestershire, North Somerset, Somerset, South Gloucestershire, Swindon and Wiltshire on notice for frequent lightning, heavy rain, hail and gusty winds.
Thoroughly active storms were already moving across the region as the warning went up. Lightning strikes were captured in Bristol this evening, giving a clear sign that the system was already close enough to affect travel, exposed buildings and roads.
Met Office warning area
The Met Office said the warning also covered parts of East of England, London and South East England, but its South West alert was the one running until 9pm. In practical terms, that meant the most immediate risk window for affected areas was the same evening, with conditions changing quickly rather than building through the night.
The Met Office said an area of thunderstorms moving east across the area would bring frequent lightning, gusty winds, torrential rain and a few places of hail. It added that driving conditions could be affected by spray, standing water and hail, while train services could be delayed and some short-term loss of power could occur.
TORRO and thunderstorms
TORRO said thunderstorms were developing in Devon and Somerset and moving ENE broadly, with risks of large hail, strong wind gusts and a small risk of a tornado. TORRO said: "Thunderstorms are developing in Devon and Somerset, moving ENE broadly, and are expected to affect parts of Wales, as well as Wiltshire and Gloucestershire, over the coming hours. Associated risks of large hail, strong wind gusts and a small risk of a tornado with these."
That smaller tornado risk did not replace the wider warning picture; it sat alongside it. The more likely problems were the ones the Met Office listed first: lightning, difficult driving in heavy rain and localised damage from gusts or hail.
South West rainfall risk
The Met Office said the storms would move quickly, which reduces the chance of widespread heavy rain. Even so, it said a few places could still see 20-25 mm of rainfall in a short period in the most active storms, with some brief flooding possible and flooding to homes and businesses also a risk.
For people in the warning area, the immediate move is simple: avoid unnecessary travel in the worst bursts, stay clear of exposed outdoor areas and be ready for short disruptions to power and transport before the warning expires at 9pm. The storm band was already in motion, and the next change was likely to come from where the heaviest cells track next.
