Heavy rain and thunderstorms will move into southern areas during Friday night, reaching south Wales and the Midlands early on Saturday. This is likely to bring frequent lightning, possible large hail and gusty winds as well as torrential rainfall for some. Where this occurs, perhaps most likely in central parts of southern England, 25 to 35 mm of rain could fall within an hour, with possible flooding. Further slow-moving thunderstorms will develop by Saturday afternoon across southern counties of England, easing only slowly through the evening. Not all places are affected but where they occur, a renewed threat of torrential rainfall and flooding, some locations seeing 30 to 50 mm within an hour or two. Lightning, large hail and locally gusty winds could pose additional hazards.
Spray and sudden flooding could lead to difficult driving conditions and some road closures
Flooding of homes and businesses could happen quickly, with damage to some buildings from floodwater, lightning strikes or hail
Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services
Power cuts might occur and other services to some homes and businesses could be lost