The Met Office have issued a thunderstorm warning for Greater Manchester.
Heavy rain and storms will hit the region on Friday afternoon and evening, interrupting this week's sunny spell.
Met Office forecasters warn there could be some flooding and disruption in some areas.
The yellow weather alert states: "Many places will miss the storms, but where they do occur, torrential downpours could bring 30-50mm rain in a hour, with hail and lightning.
"The storms will slowly clear northeastwards on Friday night, perhaps not clearing northeast Scotland until Saturday morning."
Forecasters say there is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds
Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services
Spray and sudden flooding could lead to difficult driving conditions and some road closures.
There is a small chance that some communities become cut off by flooded roads, forecasters warn.
Certain areas could suffer power cuts - other services to some homes and businesses could be lost too.
Earlier on Wednesday warnings were issued about UV levels, which are going to be “exceptionally high” over the next couple of days.
Met Office meteorologist Alex Burkill said that UV levels will be “reaching eight across many places and will be reaching nine across parts of Devon and Cornwall tomorrow.
Shoppers have also been advised to be aware they could be forced to spend extra time in the sun as a result of social distancing measures.
