With large amounts of energy again available in this atmosphere storms could be severe, with torrential downpours and large hail.
30 mm of rain is possible in less than an hour, with as much as 50 mm possible in 3 hours very locally.
A stunning video of the lightning storm that swept across the region last night has been posted on Twitter.
Nathan McMillan took the video in Eastriggs, in Dumfries and Galloway.
Isolated heavy, and possibly severe, thunderstorms are expected to develop on Friday evening.
These are likely to become more frequent later and spread northwards towards southern Scotland.
Some torrential downpours are possible leading to localised surface water flooding, with large hail and frequent lightning also possible hazards.
Here's some of the best photos of the thunderstorms that captivated Cumbria, and the South of Scotland.Read the full story ›
Thunderstorms hit the region throughout the night.
This dramatic picture was taken overlooking St Bees Head.
Do you have a thunderstorm picture you'd like to share? Please e-mail it to firstname.lastname@example.org
Temperatures in Carlisle reached 30.8C today, making it the third hottest day in July since records began.
Records first started in the early 1960s.
The hottest July day since then was in 2006, with temperatures topping 31.4C.
Isolated heavy, and possibly severe thunderstorms are expected to develop late Wednesday afternoon across parts of Northern England and Southern Scotland.
Some torrential downpours are possible leading to localised surface water flooding, with hail and frequent lightning also possible hazards.
Visit the Met Office Warning page here
A dry morning with periods of strong sunshine helping temperatures to rise quickly.
Becoming hot through the afternoon, and this could trigger some thunderstorms.
Breezy, especially along the coast. Maximum Temperature 29°C.