Isolated heavy, and possibly severe, thunderstorms are expected to develop during Wednesday afternoon across parts of Central and Southern Scotland.
According to the Met Office, some torrential downpours are possible leading to localised surface water flooding, with large hail, squally winds and frequent lightning also possible hazards.
The public should be aware that there is a chance of some very localised significant disruption, though uncertainty remains regarding the areas most at risk from storms, and many areas will miss these altogether and stay dry.
The Met Office chief forecaster said: “A hot and increasingly humid airmass now lies across much of the UK.
“This airmass is conducive to isolated thunderstorm development during the afternoon and into the evening.
“Storms could be severe, with torrential downpours and gusts to 50 mph with 20-30 mm of rain possible in an hour.”
The warning is valid from 4pm until 11.50pm on July 1.