For a portion of Wales and south-west England, a yellow weather warning is in effect from early Wednesday morning until midday.
Bus and rail services may also be impacted, resulting in longer travel times, and homes and businesses may flood, disrupting power supply and other services.
“We could see quite widely across western parts of the UK 10 to 20mm (0.4 to 0.8in) of rain,” said meteorologist Greg Dewhurst of the Met Office.
“But over those higher ground spots of parts of Wales, south-west England in particular, we could see 40 to 50mm (1.5 to 1.96in) and then locally 60 or 70mm (2.36 to 2.75in) of rain.”
He warned that some flooding might result from the intense rain.
“This falling on the back of what has been a wet winter, wet month… we could see some flooding develop as we move through tomorrow morning,” he stated.
