Thunderstorms and downpours are set to bring a dramatic end to the heatwave on Friday, with the Met office issuing a yellow weather warning to come into effect from 2pm amid fears some places may receive 30mm of rain in just one hour. It follows weeks of record-breaking temperatures, the Met Office issued a string of warnings for thunderstorms warning “Heavy showers, which will become thundery in places, are expected to develop quite widely across parts of England and Wales later Friday morning and through the afternoon. A few places could receive 20-30 mm of rain within an hour,” the Met Office said in a statement.