The Met Office says slow-moving heavy showers and thunderstorms will break out across many parts of the UK from midday onwards.
There is also potential for disruption due to flooding as torrential downpours could bring “25 to 35mm rain falling in an hour and perhaps 50 to 60 mm in two to three hours in one or two places”.
The Met Office statement adds: “Lightning and hail will be additional hazards.
“These showers and thunderstorms will only slowly die out through the evening.”
Visit the Met Office website for more information.