Temperatures in the Borders could hit as high as 29°C (84°F) today according to the latest Met Office forecast.
Any low cloud will burn off to leave clear skies this afternoon and that will see temperatures rise to a peak of 29 degrees by early evening in sheltered areas, and remaining very warm throughout the night.
However, the high temperatures also bring another warning of thunderstorms developing later in the day, with the threat of potential torrential rain, particularly in the east.
Friday will start dry, bright and still warm, with a maximum temperature of 21°C, but thickening cloud will bring outbreaks of rain in the afternoon and evening.
And things will remain unsettled going into the weekend, with a warning for heavy periods of rain throughout most of Saturday and Sunday.