Preston is being told to brace for flash flooding during the weekend.
The Met Office has issued a yellow weather warning, the lowest level, for heavy bursts of rain from Saturday (27 July) lunchtime onwards.
As the city swelters in near-record temperatures the forecast is expected to change rapidly in the weekend.
A Met Office spokesman said: “Heavy rainfall may lead to surface water and flooding in a few places and travel disruption.
“There is a small chance that homes and businesses could be flooded, causing damage to some buildings.
“There is a small chance of fast flowing or deep floodwater.
“Where flooding occurs, there is a slight chance of delays or cancellations to train and bus services.
“Spray and flooding could lead to difficult driving conditions and some road closures.”
Read more: New thunderstorm warning issued for Preston
The warning of heavy rain is in force from 12noon on Saturday until 3pm on Sunday (28 July).