The Met Office has issued a yellow weather warning for torrential rain and thunderstorms over the weekend and into Bank Holiday Monday.
As much as 30mm, possibly 40mm of rain an hour could fall in places and lightning strikes are also said to be possible, which will bring a chance of power cuts.
Forecasters say the downpours could result in some disruption, with sudden flooding of roads, transport routes, homes and businesses possible.
The weather warning is in place between midday on Sunday and midday on Monday.
