Thunderstorms and flooding presenting a “danger to life” will sweep across Scotland on Saturday.
It comes as temperatures are set to soar into the 20s, reaching as high as 27C.
Heavy rain and lightning will likely mean delays and disruption to travel, including train and bus services.
The Met Office said businesses and homes could be flooded due to sudden downpours and that buildings could be damaged by lightning strikes, hail and strong winds.
The yellow weather warning comes into effect from 9am on Saturday until midnight.
It covers most of the Highlands, central belt and the Scottish Borders, with parts of Aberdeenshire, Moray, Tayside and Fife also affected.
It comes as festivalgoers have been urged to brace for downpours as they attend TRNSMT at Glasgow Green over the weekend.
Forecasters have warned fast flowing water could pose a danger to life and some communities could be cut off by flooding, with as much as 50mm of rain falling in some areas over a short space of time.
Drivers have been urged to take care on roads and there are warnings train and bus services could also be affected by the weather.