Heavy rain could spark travel disruption across much of the UK, with a warning that flooding in some places could cause “danger to life”.
The Met Office has issued an amber warning for rain across parts of north Wales and northwest England, including Manchester and Liverpool, for 24 hours from midday on Wednesday.
Fast-flowing or deep floodwater is “likely”, according to the forecaster, and a good chance some communities could become cut off, suffer power cuts and see train and bus services cancelled.
A yellow warning for rain covers the north of England, the Midlands and north and central Wales until 6am on Thursday, while another is in place for southern and eastern Scotland from midday today until 6pm tomorrow.
Much of the south coast is likely to see lightning, with a yellow warning for thunderstorms in place from 8am until 7pm on Wednesday.
Chief meteorologist Andy Page said areas exposed to strengthening northerly winds are most likely to see the highest rainfall.
Northern areas are expected to remain cloudy and wet on Thursday, but southern parts can expect drier conditions, with sunshine becoming more widespread by the end of the week.
The news is better for bank holiday Monday, which is expected to be dry for much of the country, feeling warm in the sunshine.