The Met Office has warned that intense thunderstorms could cause disruption in parts of Wiltshire later today (Tuesday).
Whilst many areas will miss them and remain hot and sunny, isolated thunderstorms are possible this afternoon and into the evening.
These could bring frequent lightning, large hail, gusty winds and the potential for 30mm of rain in less than an hour.
The alert highlights the potential for heavy downpours, lightning, hail and strong winds in a small number of locations.
Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services.
There is also a slight chance of power cuts, with some homes and businesses potentially losing electricity and other services.
Spray and sudden flooding could lead to difficult driving conditions and some road closures.
The forecaster said there is a small chance that homes and businesses could be flooded quickly, with possible damage to buildings from floodwater, lightning strikes, hail or strong winds.
Residents are being urged to take precautions if storms develop.
Anyone caught outside who hears thunder is advised to seek safe enclosed shelter, such as a car.
People should not shelter under or near trees, or other structures which may be struck by lightning, and those on elevated ground should move to lower ground.
Householders are also encouraged to consider whether their property is at risk of flash flooding and, if so, prepare a flood plan and emergency flood kit.
Before gusty winds arrive, residents should check that moveable objects or temporary structures are secured. This includes bins, garden furniture, trampolines, tents, gazebos, sheds and fences.
Motorists are advised to check road conditions before travelling, while passengers should monitor bus and train timetables and amend plans if necessary.
The Met Office said people cope better with power cuts when they have prepared in advance. It recommends gathering torches and batteries, a mobile phone power pack and other essential items.
Weather warnings can change quickly, and when one is issued people are advised to stay up to date with the forecast in their area.
