Thunderstorms could affect the following areas: Central, Tayside & Fife, South West England, North East England, Northern Ireland, Grampian, Wales, West Midlands, Highlands & Eilean Siar, London & South East England, North West England, East England, Dumfries, Galloway, Lothian & Borders, Yorkshire & Humber, Esat Midlands and Strathclyde.
The extreme weather conditions could cause homes and businesses to be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.
Met Office warned that where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services.
Spray and sudden flooding could also lead to difficult driving conditions and some road closures.
Finally, there is a slight chance that power cuts could occur and other services to some homes and businesses could be lost.