The Met Office has issued a yellow weather warning for thunderstorms across parts of Scotland on Sunday.
The warning, which comes into effect at 2pm and lasts until midnight, applies to most of the central belt.
The Met Office warns that flooding of homes and businesses could happen quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.
Flooding may also cause delays and some cancellations to train and bus services or power cuts in some areas.
Some large areas of rain are likely, with some embedded intense rainfall predicted, that could see 70mm or more in a few hours in some locations.
A cold front will gradually move south through the weekend after starting the far northwest of the country.
The change will bring the risk of thundery downpours in some areas on Sunday.
However, there is still the possibility of high temperatures remaining, particularly in the southeast which could even see peaks of 32C on Sunday.
Met Office chief meteorologist Paul Gundersen said: “Although much of the UK will see high temperatures and sunny skies continue on Saturday, in what has a possibility of being the hottest day of the year so far, there’s also the potential for some thunderstorms, which has resulted in a Yellow Warning being issued for much of central England and parts of east Wales.
“Temperatures will begin to trend downwards from Saturday in the far northwest of Scotland, with a cold front gradually moving south through the weekend, bringing with it the risk of some heavy and thundery downpours on Sunday as well. However, the southeast will hold on to the high temperatures the longest and could still reach 32C on Sunday.”