The Met Office has issued a yellow warning for the West Midlands for hit-and-miss thunderstorms from 10am on Monday, with the storms predicted to run through to Tuesday night.
A spokesman for the Met Office said: "Whilst some places will miss them, thunderstorms and areas of heavy rain seem likely to develop quite widely on Tuesday across parts of England and Wales.
"20-30 mm of rain is possible within an hour, but where areas of thundery rain become slow-moving, some places could see 50 mm in less than three hours.
"There is a low probability that higher totals could occur in a few spots over the course of the day, while hail and frequent lightning are likely additional hazards for some places.
"There is considerable uncertainty at this stage in regional and county level focus."
While any rainfall may be seen as a relief after four days of heatwave conditions, the Met Office has predicted some disruptions.
These include spray and sudden flooding, which could lead to difficult driving conditions, as well as damage to buildings from floodwater, lightning strikes and strong winds.
Other disruption may come from delays and cancellations to train and bus services and power cuts and other services being lost to homes.
A spokesman for the Met Office said: "Hit-and-miss thunderstorms likely to develop through Monday, producing some torrential downpours for some spots, and possible disruption.
"Spray and sudden flooding could lead to difficult driving conditions and some road closures.
"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.
"There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost."