The Met Office has issued a yellow weather warning for thunderstorms across much of Wales.
The warning is in effect from midnight until 1pm tomorrow, June 12.
Heavy rain and thunderstorms are expected to move northwards, potentially leading to travel disruptions in some areas.
The Met Office has warned of possible difficult driving conditions due to spray, standing water, and hail, which could result in longer journey times for motorists and bus users.
Train services may also experience delays.
There is a likelihood of short-term power cuts and disruptions to other services.
The area of rain will make its way across parts of southwest England and Wales during Thursday morning, before clearing later in the day.
Locally, the rain will be heavy and accompanied by thunderstorms, with some areas potentially receiving 10-20mm of rain in an hour and 30-40mm in three hours or less.
This could lead to disruptions.
At times, winds may also be strong, with gusts reaching 40-50mph around hills and coastal areas.
The Met Office has advised people to avoid travelling by road during these potentially dangerous conditions.
If travel is necessary, caution should be exercised.
It is not safe to drive, walk, or swim through floodwater and should be avoided where possible.
If affected by fast-flowing or deep water, people should call 999 and wait for assistance.
The Met Office has also warned of the dangers of being outside in high winds and/or lightning, suggesting people avoid walking or sheltering close to buildings, trees, or other structures that could be struck by lightning.
They advise that if you hear thunder and cannot reach a safe enclosed shelter, you should crouch down in a ball-like position with your head tucked in and hands over your ears, making minimal contact with the ground and staying away from objects that conduct electricity.
Before the arrival of gusty winds, people should ensure that movable objects or temporary structures, such as bins, garden furniture, trampolines, tents, gazebos, sheds, and fences, are well secured.
The yellow warning has a medium likelihood and a low impact.
The affected areas in Wales include Blaenau Gwent, Caerphilly, Carmarthenshire, Ceredigion, Monmouthshire, Newport, Pembrokeshire, Torfaen, and Vale of Glamorgan.