The warning is in place between 2pm and midnight on Friday. Most places will be dry but there is the potential for slow-moving thundery downpours in places. There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater. Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services, particularly during the evening rush hour. Spray and sudden flooding could lead to difficult driving conditions with the possibility of road closures. The Met Office says there is a slight chance that power cuts could occur and other services to some homes and businesses could be lost.