Some areas could see the late spring drought break dramatically on Saturday. Thunderstorms could bring torrential rain, with associated surface flash flooding. Other hazards include hail, lightning and high winds.
A big caveat for those in the warning area though. Many areas may well stay dry. We cannot forecast the exact location of thunderstorms and heavy rain. The risk that they will occur in a region can be flagged, but not exactly where they will crop up.
So, if you are planning an event, stay weather aware and be prepared to change plans as needed.
https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings#?date=2023-06-10
On Sunday, the risk of storms continues, but perhaps not quite as high as Sunday and I think the risk area will shift more eastwards and perhaps northwards.