Met Office has issued a yellow warning in place for thunderstorms from 1 pm to 11 pm today. Thunderstorms developing this afternoon may bring some travel disruption and flooding for a few places.
The Met Office says properties could flood quickly, with damage to buildings from floodwater, lightning strikes, hail or strong winds.
Travel disruption is also expected, with delays or cancellations to bus and train services.
Road conditions could also be affected and some roads could shut.
Some communities could become cut off if roads flood.
There is also the risk of power cuts and other services.