Thunderstorms expected in southern UK after warm September spell

The Met Office has issued a yellow weather warning for thunderstorms affecting a significant portion of southern England and Wales. This warning is in effect from 12pm to 8pm on Friday, followed by another warning from 1am to 11:59pm on Saturday. The thunderstorms are expected to develop more widely, with early thundery showers on Friday leading to heavy rain, strong winds, and large hail. The area impacted stretches from central London to Cornwall. Forecasts indicate that some regions could experience around a third of a month’s rainfall in just one hour, with up to 25mm expected in the most affected areas. As the weather system progresses into Saturday, the warning will cover all of Wales, the south west, and large parts of the Midlands. Scattered showers and thunderstorms are anticipated to spread northwestward, particularly later on Friday night and throughout Saturday. The intensity of the storms may lead to significant rainfall, with estimates suggesting 50-70mm could fall in a few hours, which is comparable to the average rainfall for the entire month of September. The most severe storms are likely to occur on Saturday afternoon and evening, particularly in southern England, the Midlands, and eastern Wales, bringing the risk of hail and frequent lightning. The Met Office has cautioned that there is a slight chance of power cuts and disruptions to services for homes and businesses. Additionally, flooding poses a risk, with a small chance of danger to life due to fast and deep floodwaters, highlighting the potential severity of the upcoming weather conditions.