Heavy rain could spark travel disruption across much of the UK, with a warning that flooding in some places could cause a “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.
Meanwhile, a yellow warning for rain is in place for the north of England, the Midlands, and northern Wales until 6am on Thursday, with showers also expected in the south-east between Norwich and Bath.
Another yellow rain warning will then come into place at noon on Wednesday for Scotland, covering the south and east of the country, which will run until 6pm on Thursday. The Met Office then issued a third yellow warning for thunderstorms for much of the south coast of England from 8am to 7pm on Wednesday.
Met Office meteorologist Alex Burkill said: “Some areas are really going to see a lot of heavy, persistent rain through a big chunk of Wednesday. It is going to be a pretty wet picture as we go through the rest of the week for many places.
“There is some uncertainty as to exactly where we are going to see the heaviest rain and where is most likely to be impacted”.
The weather forecast says heavy and prolonged rainfall is expected from an area of low pressure arriving from the east, which has brought downpours to parts of central Europe overnight.
Many places across the UK could see 30-40mm of rain, while a few areas may receive 70-90mm as heavy rain moves northwards in England throughout Wednesday. The Met Office said there is a small chance a few upland areas could see up to 50mm in the mountain in north Wales.
A Met Office spokeswoman said: “The precise track of the low pressure which would determine where the rainfall comes is still uncertain and is something we are keeping an eye on.
“We would encourage people to keep an eye on the forecast over the next couple of days to see how that evolves”.
Chief meteorologist Andy Page said areas exposed to the strengthening northerly winds are most likely to see the highest rainfall.
Northern areas of the UK are expected to remain cloudy and wet on Thursday but drier further south with brighter conditions becoming more widespread by the end of the week and temperatures hitting highs of up to 21°C.
Bank holiday Monday is expected to be dry for much of the country, although there remains the threat of showers after the more settled conditions.