The Met Office weather warning for the predicted weekend thunderstorms has been upgraded from yellow to amber for most of England and Wales on Saturday.
Thunderstorms have already hit some parts of the Anglia region through Friday morning but more downpours are expected over the weekend.
Heatwave conditions are expected across the region today with temperatures forecast to rise to 32°C (90°F)
"Several areas of heavy, thundery showers will develop over England and Wales from Friday night before moving northwards during Saturday. Not everywhere within the warning area will see thunderstorms, and indeed some spells of warm sunshine are expected at times, but where thunderstorms do form, some torrential downpours are likely with frequent lightning, large hail and locally strong gusts. Significant flooding is possible where these do occur from surface water as well as from small, fast-responding watercourses."