Thunderstorms and heavy rain could bring flooding to parts of the south-west of England over the weekend. The Met Office has issued a yellow thunderstorm warning, which runs from 4am to 9pm on Sunday. Meteorologists said there was a “small chance of flooding and disruption from heavy showers and thunderstorms” on Sunday in a few places, including power cuts. “There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from flood water, lightning strikes, hail or strong winds,” a Met Office spokesperson said. They also said it could lead to difficult driving conditions and some road closures, as well as cancellations to some train and bus services. Thundery downpours are likely to hit the south of England, the Midlands, the north of England and eastern parts of Wales on Sunday. “A few showers and isolated thunderstorms are expected to develop across parts of southern England on Saturday night, but by Sunday morning there is an increasing risk of more active and organised heavy showers and thunderstorms moving in to, or developing across, parts of southern England,” the spokesperson said. “The risk of storms will then steadily transfer broadly northwards through the afternoon and into the early evening. The extent of these thunderstorms is very uncertain, and many places will miss them, but where they do occur, 30-40mm of rain may fall in less than an hour with perhaps over 75mm in one or two places, leading to a chance of flooding and disruption. “Frequent lightning strikes and hail will be additional hazards, most likely across southern and central England.” Summer has been cooler than usual in the UK with “slightly below average sun”, the latest Met Office statistics show. Rainfall has varied between regions but has been average. A heatwave swept parts of the UK in September last year, with temperatures topping 30C in some areas for seven consecutive days.